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The End of Mathematical Proofs by Humans?

vivin writes "I recall how I did a bunch of Mathematical Proofs when I was in high school. In fact, proofs were an important part of Math according to the CBSE curriculum in Indian Schools. We were taught how to analyze complex problems and then break them down into simple (atomic) steps. It is similar to the derivation of a Physics formula. Proofs form a significant part of what Mathematicians do. However, according to this article from the Economist, it seems that the use of computers to generate proofs is causing mathematicians to 're-examine the foundations of their discipline.' However, critics of computer-aided proofs say that the proofs are hard to verify due to the large number of steps and hence, may be inherently flawed. Defenders of the same point out that there are non computer-aided proofs that are also rather large and unverifiable, like the Classification of Simple Finite Groups. Computer-aided proofs have been instrumental in solving some vexing problems like the Four Color Theorem."

549 comments

  1. Science by AI by MaDeR · · Score: 2, Insightful

    I think that in far future all science will be done by AI, because knowledge will be too complicated and complex to understand for even most inteligent human on chemical boost/genetic engineered/stuffed with chips.

    --
    What modern Obelix would say today? Of course, "Those crazy Americans!".
    1. Re:Science by AI by FleaPlus · · Score: 5, Interesting

      This reminds me of a Nature paper from last year:

      Functional genomic hypothesis generation and experimentation by a robot scientist

      The question of whether it is possible to automate the scientific process is of both great theoretical interest and increasing practical importance because, in many scientific areas, data are being generated much faster than they can be effectively analysed. We describe a physically implemented robotic system that applies techniques from artificial intelligence to carry out cycles of scientific experimentation. The system automatically originates hypotheses to explain observations, devises experiments to test these hypotheses, physically runs the experiments using a laboratory robot, interprets the results to falsify hypotheses inconsistent with the data, and then repeats the cycle. Here we apply the system to the determination of gene function using deletion mutants of yeast (Saccharomyces cerevisiae) and auxotrophic growth experiments. We built and tested a detailed logical model (involving genes, proteins and metabolites) of the aromatic amino acid synthesis pathway. In biological experiments that automatically reconstruct parts of this model, we show that an intelligent experiment selection strategy is competitive with human performance and significantly outperforms, with a cost decrease of 3-fold and 100-fold (respectively), both cheapest and random-experiment selection.


      New Scientist also had an article on it: "Robot scientist outperforms humans in lab."

    2. Re:Science by AI by Zork+the+Almighty · · Score: 4, Insightful

      Well at least in regards to math, I stongly doubt that this will ever be the case. Mathematics is developed over decades and centuries. With a few notable exceptions, it doesn't just fall out of the sky in textbook form. Most areas of math started out as a giagantic mess (ex; calculus, linear algebra, even geometry), and it has taken the work of countless researchers, authors, and teachers to distill and refine it. This process will continue, and it is inevitable that the subjects which baffle us today will be hammered out and taught to grade school students eventually. Well developed theory makes mathematics easier, and this in turn fuels new discoveries.

      --

      In Soviet America the banks rob you!
    3. Re:Science by AI by Anonymous Coward · · Score: 0
      By that time, I think your "most intelligent human" will be indistinguishable from the computer based on the stuffing of chips that you refered to.

      I imagine both will be a pretty tangled network of flesh&blood (natural or genetically engineered) and more traditional hardware.

    4. Re:Science by AI by Squalid05 · · Score: 1

      Science by AI? That little robot/boy knows nothing.

      --
      To dare, is to do.
    5. Re:Science by AI by Poltras · · Score: 2, Insightful
      I think that even if we are taught the solutions in highschool, some proofs in the future might not be provable by humans.

      We'll have to agree to the result and learn it, without knowing if it is true. Some proof will become impossibly large and complex, and with it will bring theorems that are more complex but still understandable... yet further proofs will be based on those theorem, and so on.

      So yes, I think the theorems proven this way will be taught in highschool, but not the proofs in theirselves. After all, everyone has a limit, we just need to find the global limit to humankind, which comes closer and closer with the use of the computer.

    6. Re:Science by AI by Chris+Kamel · · Score: 1

      you seem to watch way too many sci-fi movies

      --
      The following statement is true
      The preceding statement is false
    7. Re:Science by AI by MaDeR · · Score: 1

      I don't think so. Human is bordered, bounded by (paradoxically) his universality. Artifical Inteligence can be construced in one specific task in mind - in this case, resolving science questions. And brain of AI can be much larger than human brain and made from scrath from materials totally different than brain tissue.

      --
      What modern Obelix would say today? Of course, "Those crazy Americans!".
    8. Re:Science by AI by rookworm · · Score: 5, Insightful

      I concur. Math will always be about insight. The best math is simple and shows why the result is true. Most mathemeticians are unsatisfied by the four-colour proof because it does not satisfy these two conditions. Even if computers are eventually able to discover such proofs, mathematicians will still have to ask the computers to search for them. We must remember that problems like solving certain differential equations used to be difficult and involved, but now thanks to computers, we don't have to worry about them as much. The same will apply for very specialized results. The big theorems will still be up to humans to prove. Think of computer- assisted math as a kind of spellchecker or Googe suggest. Computers replacing mathematicians completely is about as far-off as computers replacing poets or historians.

      --
      The toad can't burp - and for some reason can't fart either, so it swells up and eventually explodes. --Anonymous Coward
    9. Re:Science by AI by smallguy78 · · Score: 1

      can't spell hyper either (hiper? maybe hipper - cooler links?)

      --
      Nothing costs nothing
    10. Re:Science by AI by MaDeR · · Score: 1

      Texts, rather than movies. "Golem XIV" by Stanislaw Lem is great and inspiring... ;)

      --
      What modern Obelix would say today? Of course, "Those crazy Americans!".
    11. Re:Science by AI by Sinus0idal · · Score: 1

      Someone always has to program the computers.

    12. Re:Science by AI by MaDeR · · Score: 1

      Well, what if lesser AI starts programming greater AI? If AI is possible (thats it: human intelligence can create something smartet than himself), then AI can create better AI just as human can create AI.

      --
      What modern Obelix would say today? Of course, "Those crazy Americans!".
    13. Re:Science by AI by Cyberax · · Score: 5, Informative

      Well, Economist should learn some REAL math. The first thing they should learn is math logic.

      It has been PROVEN (and it's a well-known fact) that it's impossible to create a Turing machine which will determine if a given expression is true or false (see Incompleteness theorem for details).

      For example, it's impossible to find answer to CH (continuum hypotesis) in ZFC (Zermelo-Fraenkel + Choice axiomatics).

      In short: some problems can't be solved in existing theories, they require creating a new theories with new axioms. It's non-formalizable process (it's also proven), so no computer can do this.

    14. Re:Science by AI by mangu · · Score: 3, Interesting
      it has taken the work of countless researchers, authors, and teachers to distill and refine it.


      What you and others fail to grasp is that computers are evolving rapidly, human brains aren't. Our current computers are still far from having the data processing capability of a human brain.


      In rough orders of magnitude, a human brain has 1e11 neurons, with 1e3 synapses each, doing 1e2 operations per second. Considering that a neuron can be emulated by a multiply-add operation, we would need 1e16 such operations per second to emulate a human brain.


      A 3 GHz Pentium can do 1e10 floating point multiply-add operations per second, so a human brain is roughly equivalent to one million desktop computers. Therefore, Moore's law tells us that we still need 30 years of progress before we have a human-equivalent computer, but in 60 years a desktop computer will have the data processing power of a million human brains.


      We have absolutely no way to predict the consequences of this. But I'm sure that, unless we connect our brains directly to computers, we will be left hopelessly behind.

    15. Re:Science by AI by Anonymous Coward · · Score: 0

      So finally we will have a use for AI. Doing what the Ancient Greeks did several thousand years ago. I suppose that's more impressive than simulating the nervous system of a Worm with a Neural net, but only just. What a waste of money and time.

    16. Re:Science by AI by Anonymous Coward · · Score: 0

      But I'm sure that, unless we connect our brains directly to computers, we will be left hopelessly behind.

      Yeah, right. The great AI machine will be delivered in the same week as my flying car. Taking orders now, please form an orderly queue.

    17. Re:Science by AI by dynamol · · Score: 3, Informative

      It is quite a large step to go from raw computing power to intteligence. Sure computers will eventually have way more processing power than we humans do..hell they do right now if you assign them to a certain task, but that is a far cry from being intellent. With that said I do side with the camp that says computers will do most mathematical proofs in the coming decades...why? Because researchers will find a way to get computers focused on this task...and as I already mentioned computers are way more powerful than our brains on a focused task.

    18. Re:Science by AI by plupster · · Score: 2, Interesting

      Never ever is a long time... To quote from the excellent book (I just started reading) Artificial Intelligence: A modern approach

      Even if we grant that computers have limitations on what they can prove, there is no evidence that humans are immune from those limitations. It is all too easy to show rigorously that a formal system cannot do X, and then claim that humans can do X using their own informal method, without giving evidence for this claim.
    19. Re:Science by AI by DRobson · · Score: 1

      Umm, its really not that far out. Neural networks, while a gross simplification and exponentially smaller in size are essentially tiny brain like pattern recognizers. In theory we could build something as powerful as a brain today if we had the raw processing power available. Then again I'm not anywhere near an expert in the field so I could be grossly incorrect.

    20. Re:Science by AI by Sara+Chan · · Score: 2, Interesting
      In rough orders of magnitude, a human brain has 1e11 neurons, with 1e3 synapses each, doing 1e2 operations per second. Considering that a neuron can be emulated by a multiply-add operation, we would need 1e16 such operations per second to emulate a human brain.

      A 3 GHz Pentium can do 1e10 floating point multiply-add operations per second, so a human brain is roughly equivalent to one million desktop computers. Therefore, Moore's law tells us that we still need 30 years of progress before we have a human-equivalent computer, but in 60 years a desktop computer will have the data processing power of a million human brains.

      If this is right, then the 1e5 networked computers that are currently used by Google are a tenth of the way there. And 1e4 networked computers (available at some other institutions) are 1% of the way there.

      So, if you're right (and I'm not saying you are or aren't), and we just need to work on software to take advantage of the hardware, then it is really pretty scary.

    21. Re:Science by AI by DRobson · · Score: 1

      Arghh, sorry. Lack of coffee, didnt properly read the grandparent. Still, not that far off in any case ;)

    22. Re:Science by AI by Rune+Berge · · Score: 5, Funny

      Yeah, right. The great AI machine will be delivered in the same week as my flying car. Taking orders now, please form an orderly queue.

      According to rumors it will be bundled with Duke Nukem Forever.

    23. Re:Science by AI by kisak · · Score: 1
      I think that in far future all science will be done by AI, because knowledge will be too complicated and complex to understand for even most inteligent human on chemical boost/genetic engineered/stuffed with chips.

      I think the empahsis has to be on far future, if science will ever be done by AI. AI can't even consistently beat chess master in a simple game like chess, even though it calculates more moves per second than Kasporov is able to think in a life time. If AI can't even handle something as simple as chess as well as one human (and there has been a fair amount of research into making effective algorithms in chess, and even Big Gene got help from human chess experts that tuned the code while playing Kasparov), then AI isn't even yet on the level of simple arithmetic, not to mention real maths.

      The Abel Prize and Fields medal will be going to human researchers into the far future, that is for sure.

      --

      --- guns don't kill people, people with guns kill people ---

    24. Re:Science by AI by computational+super · · Score: 3, Funny

      On the flip side, according to my calculations, I lost e3 neurons, e1 synapses, and e0.5 operations per second to beer last weekend alone. That almost never happens to a computer.

      --
      Proud neuron in the Slashdot hivemind since 2002.
    25. Re:Science by AI by Slime-dogg · · Score: 3, Interesting

      Who's to say that neurons operate in the same way as a computer's multiple-add operations? Another little problem is that you'll need additional programming to tell the computer how to emulate the communication and interaction between neurons. I imagine that this would take far more processing power than we could ever achieve.

      We may be able to emulate the parts, but you can't just throw the parts together in a heap and expect it to work. The sum of the parts is far more complicated than the parts themselves.

      --
      You need to restart your computer. Hold down the Power button for several seconds or press the Restart button.
    26. Re:Science by AI by trentblase · · Score: 1
      If AI can't even handle something as simple as chess as well as one human

      Are you freaking kidding me?? Chess is by no means simple, and Kasporov is one of our best. I bet the majority of desktop computers could beat their users at chess.

    27. Re:Science by AI by mikael · · Score: 1

      Who's to say that neurons operate in the same way as a computer's multiple-add operations?

      The structure of the neuron is well known and has been proven by microscopic and chemical analysis. Details can be found here and here

      you'll need additional programming to tell the computer how to emulate the communication and interaction between neurons.

      From studies of the human brain, two new computational paradigms have been identified this technical report.

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
    28. Re:Science by AI by henrygb · · Score: 1

      Pour a glass of beer into a computer and see how much operational capacity it loses.

    29. Re:Science by AI by jhobbs · · Score: 2, Funny
      If this is right, then the 1e5 networked computers that are currently used by Google are a tenth of the way there.
      Tommorrow's Headline: Googlebot declares self world ruler, buys Graceland
    30. Re:Science by AI by mdwh2 · · Score: 3, Insightful

      It has been PROVEN (and it's a well-known fact) that it's impossible to create a Turing machine which will determine if a given expression is true or false

      Surely you mean it's impossible to create a turing machine that will determine if all expressions are true or false - ie, that there will always exist an expression that cannot be proved or disproved? I don't see how this prevents a computer proving or disproving a statement where such a proof exists.

      Also I don't see how a turing machine is different to a human. We can't prove whether the continuum hypothesis is true or not in ZFC, that doesn't mean that we can't prove things at all.

    31. Re:Science by AI by ExtraT · · Score: 1

      Tommorrow's Headline: Googlebot declares self world ruler, buys Graceland

      And I, for one, welcome our new GoogleBot overlord.....

    32. Re:Science by AI by kabocox · · Score: 1

      Well at least in regards to math, I stongly doubt that this will ever be the case. Mathematics is developed over decades and centuries. With a few notable exceptions, it doesn't just fall out of the sky in textbook form. Most areas of math started out as a giagantic mess (ex; calculus, linear algebra, even geometry), and it has taken the work of countless researchers, authors, and teachers to distill and refine it.

      You just gave me this vision: a supercomputer in a solar powered blimp doing math research running a few nontrivial programs. 1 it uploads all the "new" discoveries made. 2. it tries to simplify math and teaching of math to humans.
      3. Once a year it generates a text book following the same basic pattern: Front of book stuff. Table of contents, introduction, .5-1.5 of teaching or proofing a concept then .5-1.5 pages of problems. It also solves all the problems, puts about a third of them in the back of the book and all the rest for the problem solving edition of the book. It does that until the book grows to about 800 pages total. It instantly copy rights it all, and puts all up on its own website, and then sends it to its usual publisher.
      Then it uses handy dandy print on demand tech that we have now to print out about 30 copies of the text book... Then comes the hard part... It flies around the globe, parachuting the book to its biggest academic rivals.

      When math books fall from the sky, it will a very bad time to be a math professor.

    33. Re:Science by AI by Jagasian · · Score: 2, Informative

      Yes you are grossly incorrect. Most neural networks do not scale, and in fact perform best when they are smaller in size. Furthermore, they are such a gross approximation of a human's neurons that they don't really model them at all. Finally, neural networks do a very simple and basic operation, typically they associate a numerical value with another numerical value. There is allot more to intelligence than that!

    34. Re:Science by AI by Anonymous Coward · · Score: 0

      I agree that a brain in general can (and will eventually) be simulated in a computer. Hence, human-level AI seems possible.

      However, it is naive to think that you can roughly figure human computing power based only on the number of neural connections, and approximate a neuron as a multiple-add operation. For example, biochemistry also performs alot of 'computation.' The levels of neurotransmitters and hormones in the brain (and blood) strongly affect how the brain responds, and this is part of the computational process. The response of all neurons are affected by local concentrations of millions of different molecules. Many of these molecules are generated and triggered outside of the brain (in the digestive system, glands, etc.). So there is alot of human computational power that neural nets ignore.

      In addition the human brain implements many efficient algorithms based on the details of the connections, and this may well be the limiting factor in eventually reproducing human IQ.

    35. Re:Science by AI by kpwoodr · · Score: 1

      "I have an idea so smart that my head would explode if I even began to know what I was talking about..."

      -Peter Griffen

      --
      This sig has been removed pending an investigation.
    36. Re:Science by AI by Mr.+Slippery · · Score: 1
      If AI is possible (thats it: human intelligence can create something smartet than himself), then AI can create better AI just as human can create AI.

      That's essential the idea behind Vinge's singularity: we create a super-human intelligence, then it creates something smarter than itself, then that intelligence creates something even smarter...in a very short time, something incredible emerges.

      Note that, in the Vingean sense, "super-human intelligence" can include "intimate" computer/human interfaces...and already, Google is as close as your cell phone, the WorldBrain in your pocket.

      --
      Tom Swiss | the infamous tms | my blog
      You cannot wash away blood with blood
    37. Re:Science by AI by thomasa · · Score: 1

      What you and others fail to grasp is that computers are evolving rapidly, human brains aren't. Our current computers are still far from having the data processing capability of a human brain.

      Mathematical work is generally a product of Human intuition. How much intuition does a computer have?

    38. Re:Science by AI by DRobson · · Score: 1
      Finally, neural networks do a very simple and basic operation, typically they associate a numerical value with another numerical value.

      But so much can be modelled with numerical values. To state it like above implies a huge limitation. Im a relative novice to things such as these but I was able to easily construct a NN which recognised handwritten digits in images with ~90% success rate. While it did in reality map a great deal of numbers to other numbers, both the input numbers and output numbers had a great deal of meaning.

      Out of curiosity, are you able to say why the networks dont scale well? Or what sort of sizes NN's become unsuitable?

    39. Re:Science by AI by tgibbs · · Score: 4, Insightful

      It has been PROVEN (and it's a well-known fact) that it's impossible to create a Turing machine which will determine if a given expression is true or false (see Incompleteness theorem [wikipedia.org] for details).

      This actually is more about the limitations of logic than the limitations of computers. Indeed, Godel's Incompleteness Theorem has nothing to do with computers--it is a proof that in any system of logic (that meets some very broad criteria) there must exist statements that are true but that cannot be derived from the postulates of the system by any sequence of logical steps. Adding additional axioms does not solve this; there always remain unprovable propositions. This limitation applies to proofs by humans as well as proofs computers. However, the fact that there are some theorems that cannot be proved does not mean that there are not many others that can be.

      However, the fact that there are some truths that are literally inaccessible from the postulates certainly suggests that there may be others that are accessible only by a very large number of steps, effectively requiring computers. I wonder if anybody has ever attempted to prove this?

    40. Re:Science by AI by tgibbs · · Score: 1

      The structure of the neuron is well known and has been proven by microscopic and chemical analysis. Details can be found here [purdue.edu] and here [nih.gov]

      Certain aspects of neuronal structure are known. But the structure of neuronal neurotransmitter receptors, which are clearly crucial for neuronal signaling is in general not known in detail, nor can it be derived computationally (folding and dynamics of protein macromolecules remains computationally intractable). Similarly, there are many aspects of their function that are not known in detail. Probably much of that detail is dispensable, but we do not know enough about cognition to understand what is crucial and what is not.

    41. Re:Science by AI by thuh+Freak · · Score: 2, Funny
      Computers replacing mathematicians completely is about as far-off as computers replacing poets or historians.

      hey, don't ruin my hopes and dreams.

      --
      I wish that I was a catfish.
    42. Re:Science by AI by FuzzyDaddy · · Score: 2, Insightful
      The point of the undecidability theorem is that mathematics is not merely a set a formal rules. Pre-Godel, there was a move (for example in the Principia Mathematica) to formalize the proof process and reduce mathematics to a mechanical exercise. Godel showed that a human intuition of what the symbols meant was meaningful.

      In the case of the continuum hypothesis, mathematicians are hoping to come up with and axiom that "sounds true" and makes sense that will settle the question. This is Godel's legacy - that we can think about whether an axiom is "right", and that mathematics is no purely an excercise in manipulating symbols by fixed rules.

      That's the difference between humans and today's computers. We can't prove the continuum hypothesis with the existing axioms either, but perhaps we can find a "good" axiom that will resolve the question.

      That being said, a great deal of mathematics is manipulating symbols by fixed rules. Originally we talked about "computations" - manipulating numbers. Then we moved on to algebraic equation solvers and other symbol manipulation (a la Mathematica or MathCAD), and have now extended it to the range of mathematical proof. This is an important change in mathematics, but not the end human participation in it.

      --
      It's not wasting time, I'm educating myself.
    43. Re:Science by AI by HuguesT · · Score: 1

      If what you describe were true we would be able right now to simulate thought, only very very slowly, and not so slowly using a large enough cluster.

      The fact is we have no idea how to program a computer that will emulate or simulate thought, and that point hasn't evolved nearly as much as hardware has in the last 30 years. Mostly we have tried many ways which have essentially not worked.

      Nothing is telling me that we will discover that way in the next century or so. Possibly computers are the wrong paradigm.

    44. Re:Science by AI by mrogers · · Score: 1
      The multiply-adds are only the tip of the iceberg, think about the memory reads and writes. You'll need 10^11 words (0.4 terabytes) to store the activation levels of the neurons, 10^14 words (400 terabytes) to store the weights of the synapses, and every byte will have to be accessed 100 times a second.

      The processing is probably quite parallelisable because most connections between neurons are short-range, but even if you think of it as 1,000,000 processors with half a gigabyte of memory each, then desktop machines already have the necessary memory and processing power, but memory bandwidth is where we need to see improvements.

      Perhaps it would be better to put specialised multiply-add units on the memory chips themselves. But I don't think half a petabyte of SRAM is ever going to be cheap. ;-)

      I wonder how much heat would be produced by a computer emulating a single human brain...

    45. Re:Science by AI by Cyberax · · Score: 2, Insightful

      Yet we can prove that CH is _unprovable_ in ZFC, and this proof requires a whole new theory (theory of "forcing"). And it's impossible to automate the search for a new theory.

      Also, there is no general agorithm for proof searching: we can't just enumerate all true predicates in a given and we can't (generaly) determine if two predicates are equal.

      So computer is nowhere close to substitute a human.

    46. Re:Science by AI by mwood · · Score: 1

      It isn't a proof if nobody understands it. We can use mechanical aids to help our brains develop proofs, but we can't just take the machine's word for it...that's not what "proof" means.

      This is not to assert that any recent results are "wrong" in some way. But understanding by a human should be one of the standards for proof, at least among humans. Even if a mechanically-assisted proof is too laborious for humans to carry out unassisted, they must be able to explain why the result is valid.

      (A proof by AI could reasonably be accepted by other AIs even if no human can follow it, but that would have no value to humans unless we have good reason, already in place, to trust the judgment of the AIs in question. And even if we do trust them, argument from authority is weak and should not be substituted for at least making the attempt.)

    47. Re:Science by AI by SparafucileMan · · Score: 1
      However, the fact that there are some theorems that cannot be proved does not mean that there are not many others that can be.

      Just so that we keep thingsin scale here, 99.999999999999....% of all math problems are not provable/solvable. They are random information.

      The specific argument is "measure-theoretic", and Chaitin explains it all well. But it's the same as saying that the Real Numbers are Uncountable.

    48. Re:Science by AI by astar · · Score: 2, Informative

      This thread tends to confuse provability with true, a distinction that Godel clarified. Godel's result applies to any interesting formal system, of which logic is one, The result is that in any interesting formal system, some things are unproveable but we believe them to be true and some things are proveable and their negation is proveable also. So it is hard to make the further claim that any formal system can be true.

      The continuum hypothesis, due to Cantor, has been shown, partly by Godel, to be consistent with the usual axioms, but not proveable. The continuum hypothesis is that the power set of the integers is equal to the number of points on a line. Godel spend his last years searching for the axiom to add to the standard axioms, such that the continuum hypothesis would be proveable.

      Godel was a Platoist and considered intuition to be necessary to mathematics, and his theorem is generally considered to prove this. One should be cautious in that intutition is a technical terms, and is a generalization of Kantian intuition.

      Here is my ideosyncric take. Timaeous by Plato lays down the claim generally called the hypothesis of the higher hypothesis. In case of contradiction, there is an axiom that can be added to resolve the contradiction. Godel says in effect, it is good there is such an axiom, since you have to add it. And the process of adding it involves creativity. Take this with a grain of salt, but Timaeous was a favorite of Godel.

      Regarding the limits of Godel's proof, it does not necessarily apply to infinitely large axiom sets. So perhaps God has an infinite axiom set, in contradiction to the usual claim that God does not use axioms.

    49. Re:Science by AI by Chris84000000 · · Score: 1

      It should be noted that while determining the truth of an arbitrary statement is not a decidable problem (a "recursive" problem), determining the whether or not a given proof (as a string in some suitable formalization language) proves a certain fact is decidable, and is in fact in P [1].

      Determining a statement to be true requires finding a proof of it (within the limitations of Godel's incompleteness theorem). This is an automatable process and one possible algorithm is quite simple: check each possible string in the formalization language to see if it proves the statement. This will not halt if the statement is false, but will find the proof eventually if it is true. This class of problems is known as recursively enumerable. See also the Chomsky_heirarchy.

      [1] Martin, John "Introduction to Languages and the Theory of Computation" Third Edition.

      --
      Please stop misusing Catch-22 to describe chicken-egg problems or other paradoxes that are not Catch-22.
    50. Re:Science by AI by Anonymous Coward · · Score: 0

      And since only about 10% of the human brain is active at any time, we're even closer than that.

    51. Re:Science by AI by danila · · Score: 1

      That's the difference between humans and today's computers. (emphasis mine)

      Of course, today's computers can't do advanced stuff. They can't even program themselves. But that's to be expected, as the field of computer proofs is relatively young (20-something years, with most of the progress happening relatively recently).

      The grandparent poster said that coming up with new axioms is a "non-formalizable process (it's also proven), so no computer can do this." Of course, he doesn't realise what he is talking about (to be expected - he's just a human). A non-formalizable process can't be proven to produce a correct result. :) We can't really rely on human brains more than on artificial intelligence, and a computer can (in principle) invent new axioms that are just as valid as those invented by humans (and incompleteness theorem basically says that those additional axioms are every bit as good as their opposites).

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    52. Re:Science by AI by danila · · Score: 3, Informative

      Wrong.

      The theorem says that there are either true unprovable things or things that are both provable and provable to be false. An interesting formal system is either incomplete or contradictory (it can be both, but it doesn't have to).

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    53. Re:Science by AI by astar · · Score: 1

      agreed

    54. Re:Science by AI by FuzzyDaddy · · Score: 2, Interesting
      incompleteness theorem basically says that those additional axioms are every bit as good as their opposites

      Axioms don't usually have opposites. That's what makes deciding on good axioms non trivial. The parallel postulate has two possible replacements, leading to two different geometries. Neither is the opposite of the other. You could try to come up with more axioms (through every point not on a line there are exactly three lines parallel to the original line), but they might not lead to a logically consistent structure.

      Axioms are not arbitrary!

      --
      It's not wasting time, I'm educating myself.
    55. Re:Science by AI by Coryoth · · Score: 1

      Actually your sig provides a goo example for this - quintics. If you want to show that the general quintic has no solution expressible in radicals ... well you can use Abel's method, which is pretty much what a computer would do. You would get a lon complicated proof that was not especially enlightening.

      On the other hand, if you get a creative genius like Galois to attack the problem, you get what appears to be a whole lot of completely tangential unrelated ideas that, when put together suddenly prduce a simple elegant proof that explains far more about *why* the general quintic is unsolvable in terms of radicals. You also get whole new fields of mathematis based on the new directions Galois headed.

      The point is that there are things that current computer provers are good for, and there are things they aren't. Verifying/proving compex identities or statements is what they're good at. Creative insight to create new ways of exploring the old problem, and new theories, that they currently aren't so good at.

      Jedidiah.

    56. Re:Science by AI by Impy+the+Impiuos+Imp · · Score: 1

      There was a claim that certain tiling problems could not be solved via Turing machine, but that humans could solve them. This is interesting because it implies that a computer simulation of the universe, including the human brain, could not ever be 100% complete because "brains" in said universe could not solve said tiling problems.

      Is this a definitely proven statement about the tiling issue, or is it still hot air (up in the air)?

      --
      (-1: Post disagrees with my already-settled worldview) is not a valid mod option.
    57. Re:Science by AI by sixpaw · · Score: 2, Informative
      However, the fact that there are some truths that are literally inaccessible from the postulates certainly suggests that there may be others that are accessible only by a very large number of steps, effectively requiring computers. I wonder if anybody has ever attempted to prove this?
      Yes; in fact, this is true for even very simple logical systems. Presburger Arithmetic (the theory of integers with addition but no multiplication) has theorems that can only be decided in double-exponential time -- i.e., O(2^2^(kn)), where n is the length of the theorem in question. Here's Wikipedia's page on it.
    58. Re:Science by AI by Jagasian · · Score: 1

      Many applications of NNs have been used to show that increasing the size of the NN doesn't improve the effectiveness of the NN and in fact causes it to have less success.

    59. Re:Science by AI by Impy+the+Impiuos+Imp · · Score: 1

      Yes, but that's like pointing out 99.999999999999999% of all pictures cannot be compressed. Note that the same percentage are also basically random bitmaps. It's the interesting ones we care about.

      Similarly, it's the interesting math issues we are mostly concerned with, and they probably mostly have potential proofs.

      --
      (-1: Post disagrees with my already-settled worldview) is not a valid mod option.
    60. Re:Science by AI by podperson · · Score: 1

      This is a proof about the limits of logic not the limits of computers. Incompleteness states that within any system of logic there will be statements that are true or false that cannot be proven (true or false) -- by Turing machine, human being, or God.

    61. Re:Science by AI by jerald_hams · · Score: 2, Informative

      I see these brain-computer processing power comparisons on slashdot often, and they make me cringe.

      The brain is *not* a serial computer, and cannot be compared to one in any meaningful way.

      1) Parallel computations cannot necessarily be simulated on a serial computer. (http://www.andrewboucher.com/papers/parallel.htm)

      2) Why do you assume that a neuron can be simulated with a multiply-add operation? Even if the perceptron model of the neuron, where a scalar output is the linear combination of scalar inputs, had anything to do with the brain (which it almost certainly doesn't), you'd need a variable-length addition (between 1 and 100,000 inputs). Furthermore, to make the perceptron useful, you need some form of non-linear transformation on the output.

      3) Many of the 1e11 cells you're including in your calculation are used for specific, non-conscious tasks.

      4) What about the 1e13 neuroglia, whose function is still poorly understood, but have been shown to have an active role in the brain's activity? (reacting to and initiating neural activity)

      5) 1e2 "operations per seconds" (firing rate?). Action potentials are not operations performed on data, they are the data.

      Ugh, I could go on for a while...

      But please, please....the brain != serial computer. The brain is not comparable to a serial computer. And they can be compared, no one today knows enough to do it. So stop.

    62. Re:Science by AI by Impy+the+Impiuos+Imp · · Score: 1
      --
      (-1: Post disagrees with my already-settled worldview) is not a valid mod option.
    63. Re:Science by AI by Anonymous Coward · · Score: 0

      The (first) incompleteness theorem and the independence result are essentially different kinds of bunnies. The former says that for any formal theory (of a certain kind) there will be a sentence (in the language of the theory) that is true but not provable (from the axioms of the theory). The aforementioned sentence is known as the theory's "Goedel sentence." The independence result says that neither the continuum hypothesis (CH) nor its negation is provable from the axioms of ZFC. So CH isn't provable in ZFC, but it's essentially different from the Goedel sentence in that few mathematicians are prepared to say that CH is true (in the Platonic realm of sets). CH is independent of ZFC in the same sense that any two atomic sentences (e.g., 'P' and 'Q') are independent of eachother.

    64. Re:Science by AI by tumbaumba · · Score: 1

      This process will continue, and it is inevitable that the subjects which baffle us today will be hammered out and taught to grade school students eventually

      Why is it inevitable? The amount of science papers just keeps increasing and increasing. It seems rather inevitable that some branch of science will go astray sooner or later based on wrong but too dificult/imposible to verify postulate.

    65. Re:Science by AI by Anonymous Coward · · Score: 0
      It has been PROVEN (and it's a well-known fact) that it's impossible to create a Turing machine...
      Duh. A Turing machine has an infinite memory tape and therefore cannot exist in the universe. For a real finite state machine, it is trivial to write an expression that will not even fit inside the machine.
      It's non-formalizable process (it's also proven), so no computer can do this.
      Wrong. Firstly, computers are not simple deterministic automatons with boring, predictable output. They can quite easily use truly random numbers to cast about in the space of possible solutions, fuzzy logic to make educated guesses about what form a useful new axiom might have, and genetic recombination to graft ideas together in preposterous ways. Sure, most of the attempts will be crap, but a modern research computer capable of a trillion operations per second can afford to weed out a lot of crap.

      Secondly, that a deterministic machine cannot find a useful new axiom always, does not imply that it will never find one.

    66. Re:Science by AI by MyLongNickName · · Score: 1

      I DO use 10% of my brain, you insensitive clod.

      (Thank goodness for the 'Post Anonymously' option)

      --
      See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
    67. Re:Science by AI by Anonymous Coward · · Score: 0

      you compare a neuron to a cpu or computer, but this model is very inacurate. A neuron is first of all working with analog patterns. Also it work quite non-deterministic so any emulation of that with a deterministic machine, like a computer, will need 2^x times of processing power.

      Quatum computers are no solution for this problem any time soon.

    68. Re:Science by AI by danila · · Score: 1

      Correct. Sorry for making a mistake - I'm still just a human. :-(

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    69. Re:Science by AI by JadeNB · · Score: 1

      It is true that no computer can judge the truth or falsity of all postulates. On the other hand, no mathematician can, either, and yet we let them keep working.

    70. Re:Science by AI by hawkfish · · Score: 2, Insightful
      Who's to say that neurons operate in the same way as a computer's multiple-add operations?
      Indeed.
      --
      You will not drink with us, but you would taste our steel? - Walter Matthau, The Pirates
    71. Re:Science by AI by danila · · Score: 2, Interesting

      No, this is basically bullshit. Penrose allows his irrational belief to determine his science, which is a big no-no for a scientist. He postulated that human mind is not a computer and grasps every straw to show how it might potentiall be so. Since he is a renowned and respected mathematician, his views are given a modicum of respect, just sufficient to guarantee he will not shut up for about 20-30 more years (by then we will probably have self-conscious strong AI that passes the Turing test and more).

      This particular argument is patently stupid, but again, since Penrose has a big name, he gets away with it. The argument is as follows. Take two tiles that can fill the plane in a unique aperiodic way (one of Penrose's achievements was coming up with such things). Give an infinite amount of such tiles to a human and a "computer". Ask them to start tiling the plane and then ask whether the tiles can in fact tile the whole plane. Since the mosaic is aperiodical, according to Penrose the computer will not see a pattern, but a human will (the pattern being that you could always add a tile (as far as you tried), so the plane must be tileable). Penrose explains this by saying that humans have some magical "human consciousness" that allows them to have some "insight" about the world, to "understand" it, while computer doesn't have it. He then proceeds to explain this with some crackpot theories about quantum effects in microtubules in the human neurons, which is total bullshit, but again, his big name allows him to get away with spouting such garbage.

      His argument is, of course, wrong. Humans can easily see patterns, because we were programmed to see them. This, of course, doesn't mean that we are always correct, when we believe there is a pattern. For example, consider the following sequence of numbers: 1, 3, 5, 7... Is there a pattern? If you think I listed odd numbers, you are wrong. It could have been a year, it could have been some random digits, it could have been a part of a different sequence, etc.

      If monkeys could understand what an Euclidean plane is, they could reach the same conclusions as humans just as quickly. 1) You place a tile, it fits. 2) You place another, it fits. Repeat 10 times. Wow, it must be a magical pattern! This is just a heuristic that we humans have. The conclusions it helps us come to are not necessarily correct. We are not better than computers in solving the halting problem. It's just that too often we are willing to shout the answer, before we can be reasonably sure. Of course, sometimes we are lucky and the answer is correct. But we can program a computer to do just the same - it will gain the magical ability to "understand" and "see" the answer, at the price of often being completely wrong.

      Penrose is just a persistent moron, don't listen to him.

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    72. Re:Science by AI by k98sven · · Score: 1

      Calling it a "robot scientist" goes a bit too far.

      Correlation is not causation and science isn't about finding lots of empirical observations and correlations, it's about understanding why you have these correlations.

      You can build a robot which turns on and off light-switches, which will automatically make the observation that it will lead to a light going on 99% of the time. But it still takes real intelligence to understand why that happens.

      Now in this case, the robot does 'create' hypothesis itself. But only within the limits of its programming. In other words, it will automate the 'discovery' of things where you already have a very good idea of how it works.

      Now that is useful, but it's hardly going to change science as we know it. Obviously, it will never be able to discover something completely new and original (which is the most interesting kind of discovery).

      Also, it is only useful for areas where the research is being conducted in a very systematic manner, which isn't the case for most of science. In most science, it's not just a question of finding out stuff. That's usually the easier part, actually. The big problem is finding out how to find out.

    73. Re:Science by AI by Boronx · · Score: 1

      Yet we can prove that CH is _unprovable_ in ZFC, and this proof requires a whole new theory (theory of "forcing"). And it's impossible to automate the search for a new theory.

      Why do you say that? How did a human come up with the theory?

      Also, there is no general agorithm for proof searching: we can't just enumerate all true predicates in a given and we can't (generaly) determine if two predicates are equal.

      We don't know of any such algorithm. I think it's likely such an algorithm can't exist, but that doesn't mean that we won't find an algorithm that's general enough to be better than humans.

    74. Re:Science by AI by Anonymous Coward · · Score: 0

      "Our difficulty is not in the proofs, but in learning what to prove." - quote by Emil Artin

    75. Re:Science by AI by shobadobs · · Score: 1

      This thread tends to confuse provability with true, a distinction that Godel clarified.... ...The continuum hypothesis is that the power set of the integers is equal to the number of points on a line.

      You seem to be the one creating the confusion. The continuum hypothesis states that there exist no sets whose cardinality is between that of the integers and that of the real numbers. Both the continuum hypothesis and its negative have been shown to be consistent with the other axioms of mathematics.

      It is easy to prove that the power set of the integers and the real numbers have the same cardinality. Easy to understand the proof, anyway.

    76. Re:Science by AI by shobadobs · · Score: 1

      But what is this "intuition" of which you speak? Intuition might be a fancy term for describing what happens when humans recognize patterns based off of past experiences. Unless you have something you can point to and say "THIS is intuition, and computer programs can't exhibit it for this reason," I don't see any reason why they could not.

    77. Re:Science by AI by Listen+Up · · Score: 1

      This not the case at all. The use of computers is simply to speed up the use of calculations and definitions of Mathematics in order to complete analysis in a timely manner. Human beings are still the inventors of the dreams and ideas, discoverers of the truth, but the analysis of the calculations can take thousands of years of human calculation time. This is where the computers are used, as a tool to accelerate human calculation and analysis.

      A related topic to your post may be the eventual discovery of AI. The future of mankind will be changed forever in an instant.

    78. Re:Science by AI by mpeisenbr · · Score: 1

      This sounds an awful lot like hibert's program, which Godel showed to be impossible via the incompleteness theorem.

    79. Re:Science by AI by Fulcrum+of+Evil · · Score: 1

      Chess is by no means simple, and Kasporov is one of our best. I bet the majority of desktop computers could beat their users at chess.

      You think Chess is complicated? Try Go. Last I checked, there were no computers capable of consistently beating a professional level Go player.

      --
      "We returned the General to El Salvador, or maybe Guatemala, it's difficult to tell from 10,000 feet"
    80. Re:Science by AI by thomasa · · Score: 1

      I agree with you. But not in the forseeable future.
      Quantum computers will not even help. The state of the art in computer algorithms is to primitive.

    81. Re:Science by AI by Jim+Starx · · Score: 1

      Mathematics is not a careful march down a well-cleared highway, but a journey into a strange wilderness, where the explorers often get lost. Rigor should be a signal to the historian that the maps have been made, and the real explorers have gone elsewhere. -W.S. Anglin

      --
      The darkness... controls the music. The music... controls the soul.
    82. Re:Science by AI by Cyberax · · Score: 1

      Why do you say that? How did a human come up with the theory?
      You've just asked the ultimate question of cybernetics: "What is consciousness?".

      Of course, I can't answer this question :)

      We don't know of any such algorithm. I think it's likely such an algorithm can't exist, but that doesn't mean that we won't find an algorithm that's general enough to be better than humans. No, it was proven that the set of true predicates (expressions) in every incomplete theory is uncountable. So no general algorithm can exist.

      Of course, less general algorithms exist (semantic tables reductions, predicate expansions, etc.), but they are nearly useless, because they require gigantic amount of computer time to produce a proof to a hard problem.

    83. Re:Science by AI by Cyberax · · Score: 1

      It's an open question if a human brain can be simulated by Turing machine.

    84. Re:Science by AI by Zork+the+Almighty · · Score: 1

      It is inevitable if you believe that human progress will continue indefinitely. Good science develops in many different directions simultaneously. Someone will always be taking a fresh look at something, and they may develop a new approach. At the very least, the human race is forced to consider new ideas because people die and we are constantly have to teach replacements.

      --

      In Soviet America the banks rob you!
    85. Re:Science by AI by oku · · Score: 1
      This thread tends to confuse provability with true, a distinction that Godel clarified. Godel's result applies to any interesting formal system, of which logic is one,

      Sorry, not unless you clarify what you mean with 'logic'. First-order predicate logic (the logic known to most people who learned some logic and are not mathematicians) is completely formalizable. This is actually the result of Gödels completeness theorem. All true statements are provable. The set of provable theorems remains uncomputable, though.

      The continuum hypothesis is that the power set of the integers is equal to the number of points on a line.

      No, this is easily proved. The continuum hypothesis is that there are no sets that are larger than the set of integers and smaller than the power set of the set of integers.

      In case of contradiction, there is an axiom that can be added to resolve the contradiction.

      Not in most logics that we use today. A contradiction means that a statement and its negation can both be proved. But when you add more axioms, the existing contradicting theorems still hold. You can resolve incompleteness, but not contradictions. (Exceptions are logics like default logic that may loose theorems as they gain axioms. Very nonstandard.)

      Regarding the limits of Godel's proof, it does not necessarily apply to infinitely large axiom sets.

      Indeed it does not. Use all true statements as axioms, then the system is trivially complete. It ceases to be interesting, though.

      I hope that helps, Olaf

  2. Critics Reaction... by Suhas · · Score: 4, Insightful

    ...From TFA if a computer is used to make this reduction, then the number of small, obvious steps can be in the hundreds of thousands--impractical even for the most diligent mathematician to check by hand. Critics of computer-aided proof claim that this impracticability means that such proofs are inherently flawed.

    So basically what they are saying is that if the proof is too long to be checked, then it is flawed? WTF?

    1. Re:Critics Reaction... by damieng · · Score: 5, Insightful

      Yes, thats right.

      If you can't independently examine and verify your "proof" then how can it be considered proof of anything?

      --
      [)amien
    2. Re:Critics Reaction... by wwahammy · · Score: 3, Insightful

      Flawed in the sense it can't be peer reviewed to be "proven." It could be true but because it can't be independently verified then its not a proof because you can't prove it. Now whether this is truly a situation where a proof is unprovable or just people reacting to the thought of their profession being eliminating by technology is another debate entirely.

    3. Re:Critics Reaction... by oneandoneis2 · · Score: 1
      ...too long to be checked, then it is flawed?...

      You could be on to something here: That rule might apply to software too.

      How many lines of code do they reckon make up the Windows source code..? :o)

      --
      So.. it has come to this
    4. Re:Critics Reaction... by Anonymous Coward · · Score: 1, Insightful

      A proof that can't be checked is definitely flawed.

    5. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      Yeah, why not use a computer to check it?

    6. Re:Critics Reaction... by Zork+the+Almighty · · Score: 1

      If it can't be checked, it's not really a "proof" is it ? Now granted, that leaves a lot of room for leaway. For example, one could construct an algorithm for the problem and then prove that the algorithm is correct. There are other more inventive possibilities too.

      --

      In Soviet America the banks rob you!
    7. Re:Critics Reaction... by MonMotha · · Score: 3, Insightful

      A mathematical proof is nothing but a manner of convincing someone (other mathematicians) that what you assert is indeed correct, given the following presumably known, accepted as true, or otherwise previously proven "things". The whole point of a proof is that someone else knows wtf it is talking about.

      I could assert that 2+2=4. You may believe me, but have I really proven it to you? Not yet, so you don't need to believe me. If I instead say that the the cardinality of the union of two disjoint sets, each of cardinality 2, is 4, then I've (sort of) showed you that 2+2=4, assuming you accept my definitions of disjoint sets, set union, and set cardinality (which presumably I've proven elsewhere, or taken from some other source). Now do you believe me that 2+2=4?

      I could assert anything. You may or may not know if it's true. A proof is just something to back up my assertion and convince you that I'm right. Hence, if a proof is unintelligable, it's pretty darn worthless.

    8. Re:Critics Reaction... by Tomfrh · · Score: 1

      So the proof only exists if you observe it? That reminds of a certain cat experiment....

    9. Re:Critics Reaction... by Zork+the+Almighty · · Score: 4, Insightful

      Whether or not something is a proof is entirely our distinction to make. We choose the axioms on which the proof is based. To paraphrase Bill Klem (a famous umpire): when asked whether a pitch was a ball or a strike, "It isn't anything until I call it".

      --

      In Soviet America the banks rob you!
    10. Re:Critics Reaction... by Tomfrh · · Score: 1

      Whether we deem a proof correct doesn't affect whether it is or not.

    11. Re:Critics Reaction... by Sloppy · · Score: 2, Funny

      Just write a program to check it. :-)

      --
      As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
    12. Re:Critics Reaction... by idlake · · Score: 1

      If you can't independently examine and verify your "proof" then how can it be considered proof of anything?

      By programming my computer to independently examine and verify the proof. Done properly, the instructions for a computer to verify a proof can be a lot simpler than verifying the proof itself.

    13. Re:Critics Reaction... by cg0def · · Score: 0, Flamebait

      And how exacty is a computer going to prove this basic fact to you? Also if you have to ask somthing like this you are either dumb or have missed the 1st grade. Too bad for you in both cases. Oh yeah and 2+2=4 and that IS proven. There are some basic assumptions that people make and some statements are assumed to be true because there is no proof or disproof but this is not one of them.

    14. Re:Critics Reaction... by maxwell+demon · · Score: 2, Insightful

      Of course then you still have to proof that your program for proof checking is correct.

      --
      The Tao of math: The numbers you can count are not the real numbers.
    15. Re:Critics Reaction... by spagetti_code · · Score: 4, Informative
      Many proofs have been thought to have been found, only to be proven wrong years later. And that was only after years of study my mathematicians of the time. For example, from the article: this particular puzzle was twice 'solved' only to be 'unsolved' 11 years later. Consider also Wilkes proof for fermats conjecture - it was proven wrong and had to be redone.

      So the question is - how are we going to prove/disprove a computer program that proves a theorem? Program complexity has meant that all but the most trivial programs cannot be 'proven'.

      The solution, it seems to me, is per the article: get the s/w to output a series of steps using formal logic. Any series of formal logic steps should be confirmable by a 'formal logic validator', and that is the only program we need to prove correct. That will be non-trivial, but will then open the floodgates to any hacked up piece of code to be used to generate provable logic.

    16. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      The difference between mathematics and any other field (that I can think of) is the absolute nature of knowledge. Mathematics can reduce its assumptions to a very very small number. e.g. You can get amazingly far with the only assumption of "A does not equal not-A".

      In this respect, and keeping those assumptions in mind, a correct mathematical proof establishes more than just a convincing argument; it establishes truth.

      On the other hand, physics, for example, doesn't present us with truth (yet). It just has More Accurate and Less Accurate. Theorems are "proven" both on paper and empirically, and are considered "knowledge" when we can see evidence. When a better theory comes along, the older ones will just shift further towards the Less Accurate end of the spectrum.

      If the infallability of AI proofs can be mathematically proven, I'd go with that. But I'd rather a human check that particular proof, and I'm not holding my breath.

    17. Re:Critics Reaction... by prefect42 · · Score: 1

      "Oh yeah and 2+2=4 and that IS proven"

      Unless it's not of course. It could quite reasonably be considered to be 10 or 11. There are some basic assumptions that people tend to make, that aren't necessarily true.

      --

      jh

    18. Re:Critics Reaction... by gorrepati · · Score: 2, Insightful

      So basically what they are saying is that if the proof is too long to be checked, then it is flawed? WTF? Nope, that is not what they mean. If the proof cannot be verified, there is no gaurantee that the proof is correct

      --
      You will never have experience until after you needed it.
    19. Re:Critics Reaction... by A+beautiful+mind · · Score: 4, Informative
      Um. A mathematical proof is just a sequence. It doesn't have to be accepted to be true. According to the axiomatic method of proving ,you just need these things:
      • An abc (not THE abc, just one)
      • formulas
      • derivation rules
      An axiom is just a derivation rule which derives from the empty set.

      Basically, a proof is, according to the axiomatic method, is just a non-infinite sequence of formulas, which can be created by the allowed derivation rules. The whole point is that a proof for A HUMAN, and mathematical proof is different. The axiomatic system is not perfect, either. The whole Hilbert-plan is proven to be impossible to be done, thus it is not possible to prove that there are no contradictions in the axiomatic system

      I think the "MUI" axiom system is commonly used to demonstrate how it works, basically. It is too lengthy, and i'm lazy.
      --
      It takes a man to suffer ignorance and smile
      Be yourself no matter what they say
    20. Re:Critics Reaction... by nikitad · · Score: 5, Informative

      If mathematical proofs were "nothing but a manner of convincing someone", how could it be verifiable by a computer?

      Fully formal mathematical proofs depend on nothing but ability to distinguish characters, to compare text strings, and to perform substring substitution.

      To your example (2 + 2 = 4). In formal arithmetics, based on Peano axioms, there is one primary operator, let's call it s:N -> N, and s(n) is interpreted as (n + 1). "2" is _defined_ as s(1). 3 is defined as s(2), and 4 is defined as s(3). So one has to prove that s(1) + s(1) = s(s(s(1))).

      By definition of addition (remember, addition is not fundamental notion in the formal arithmetics, it's defined in terms of s-operator), a + s(b) = s(a + b), and a + 1 = s(a), so we have

      s(s(1) + 1) = s(s(s(1))),
      s(s(s(1))) = s(s(s(1)))

      Q.E.D.

      So, where proof above depends on anything but mechanically verifiable string manipulations?

      P.S., of course mathematical formulae are not strings, but rather trees, but this doesn't change a bit.

    21. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      Close, but no sigar.

      The former poster mix proof with definition, that is all.

      His point DO stick to definitions too though. If I say I have a 5 million page definition of the relationships between 1, 2, 4, + and =. This definition is worthless to mere human beings, and a more elegant and simpler definition is better and more convincing.

    22. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      I was going to post something very similar to this so thanks for saving me the effort. However one comment - even if a proof is unintelligable, if you can be comfortable that the methods (i.e. rules) through which it was derived are foolproof and you accept any initial assumptions, it is I think possible to believe a proof that has been done by a computer.

      And since proof is just about convincing people, if people trust the computer to follow the rules, and they believe in the rules, then I would argue that it is proven.

    23. Re:Critics Reaction... by mwlewis · · Score: 1

      You missed his point. Conjectures may be correct. That doesn't make them proofs. We don't call it a proof until we're certain that it's correct (even then, we're sometimes wrong). It's not the correctness, it's the proofness that's the issue here.

      --
      JOIN US FOR PONG!
    24. Re:Critics Reaction... by rsidd · · Score: 1
      By programming my computer to independently examine and verify the proof.

      If you can write a verifiable program that checks the correctness of the proof (ie, it can be verified independently that your program is correct), then the proof is verifiable.

    25. Re:Critics Reaction... by g1t>>v · · Score: 4, Informative

      Yes but a "correct mathematical proof" only establishes truth relative to the axiom system used. Because how will you ever prove that the axioms are true? (That's why they're called axioms---you cannot prove them and just have to assume the're "true".) In other words, there's no such thing as "absolute truth". (This is what Hilbert meant when he defined mathematics as "Mathematics is that subject in which we do not know what we are talking about, nor whether what we say is true.")

    26. Re:Critics Reaction... by dissy · · Score: 4, Interesting

      > By programming my computer to independently examine and verify the proof. Done
      > properly, the instructions for a computer to verify a proof can be a lot simpler
      > than verifying the proof itself.

      But even multiple computers performing a verify isn't _truly_ a verification.

      After all, how long did the Pentium division bug go _unnoticed_???

      Looks like the chip was released on March 22, 1993
      and the bug was reported on October 30, 1994

      Over a year and a half worth of time any/all such verifications obtained with the newest intel computers at the time were WRONG.

      And any guesses how they even found this bug??
      It was a human, not another buggy computer, that had to verify the data.

      Yes computers can do things faster, but ever underestimate the power of truly knowing what your doing, which so far, a computer can't grasp at all, let alone do as well as the human mind.

    27. Re:Critics Reaction... by g1t>>v · · Score: 1

      That's why we talk about "formal mathematical proofs" as opposed to "mathematical proofs". The latter are more or less vague arguments to convince the human reader that a formal mathematical proof of the theorem in question would be possible.

      In your proof above, the "mechanically verifiable string manipulations" would amongst others contain substitution (so from the theorem "a+s(b) = s(a+b)" you would be able to get get "s(1)+s(s(1)) = s(s(1)+s(1))" and so on. But it is an informal proof, not a formal one, so to get to the mechanically verifiable level, you'd have to spell out a lot more details.

    28. Re:Critics Reaction... by mario_grgic · · Score: 1

      Actually, writing a program to check it would not be necessary since validity of original program that generated the proof is enough. Which leads us to another interesting point, a program that generates the proof is just another (perhaps better since it is faster) model of mathematical reality, and since it is made by humans it shows that humans will stay superior proof writers (unless a proof generating program can also make improved copies of itself which means it's practically AI).

      --
      As the island of our knowledge grows, so does the shore of our ignorance.
    29. Re:Critics Reaction... by g1t>>v · · Score: 5, Insightful

      In general, it is impossible to prove that such a 'formal logic validator' is correct since it is not possible to prove that an axiom system is correct inside that axiom system (one of Goedel's theorems). So if you would find a proof that your validator is correct, you'd have used reasoning techniques outside the logic of your validator, and do you believe those? (If so, why didn't you include them in the validator, since now your validator clearly does not support a reasoning technique you considered valid in the first place!)

      Basically, at a certain point, you just have to "believe" that your axioms, logic, whatever you call it, is consistent. Because to prove it, you'd again need axioms, a logic, etcetera, ad infinitum.

    30. Re:Critics Reaction... by papik · · Score: 1
      So, where proof above depends on anything but mechanically verifiable string manipulations?

      I think that one of the remarks made is that there could be bugs (overflow, compiler bug, ...) in the program that does string manipulation, and for complex proofs it is too hard to find them.

    31. Re:Critics Reaction... by Sique · · Score: 2, Interesting

      It's not that easy. Fundamentally the mathematical proof consists in something else than the actual running of the program.

      The question is if the output of the program is equivalent to the problem you want to prove. Your proof actually consists of verifying that "Program Output is A" is only true if "Statement B is true" is true.

      (It's not necessary to prove also the reverse notion. "Statement B is true" doesn't need to implicate that "Program Output is A". Imagine a program that prints out "A" if it is 8pm. Then imagine the statement being "The long hand of the clock points to the 12". If the program prints out "A", then you can be sure that statement to be true for a correctly running clock.)

      In the end those proofs (Program Output is A -> Statement B is true) are as peer reviewable as any other proof.

      --
      .sig: Sique *sigh*
    32. Re:Critics Reaction... by WoodieR · · Score: 1

      but it can be " peer " reviewed -> by another AI

      --
      Question Authority before IT questions You ...
    33. Re:Critics Reaction... by grumbel · · Score: 2, Insightful

      Why? I mean you don't prove that the human verifing the proof is 'correct' either. And well, I for one think that humans make quite a lot more random errors then computers. So I don't see why you have to proof the computer, but not the human.

      One should of course ensure that the programm is correct and all as good as possible, but I don't see much difference between a proof verified by a bunch of independently written computer programms and a proof verified by a bunch of humans.

    34. Re:Critics Reaction... by grumbel · · Score: 1

      ### But even multiple computers performing a verify isn't _truly_ a verification.

      But Joe Math Prof saying: "Yep, I verified it and its correct" is? I mean sure you shouldn't do a proof with a single programm on a single architecture, but whats the difference between multiple independed developed programms on multiple different architectures and a bunch of math guys verifing the proof? Both can be wrong at times, thats why you do the proof with a lot of intepended persons/computers to be reasonably sure that it is correct.

    35. Re:Critics Reaction... by Flyboy+Connor · · Score: 1
      Flawed in the sense it can't be peer reviewed to be "proven."

      But it can. When the algorithm is published, you can implement it from scratch on a different computer. If humans are peers for humans, doesn't it make sense that computers are peers for computers?

    36. Re:Critics Reaction... by mopslik · · Score: 1

      I don't see much difference between a proof verified by a bunch of independently written computer programms and a proof verified by a bunch of humans.

      Indeed. In all likelyhood, those programs will be written by humans anyway, using similar logic as humans would apply to a proof anyway.

    37. Re:Critics Reaction... by martijno · · Score: 1
      I attended a talk by Georges Gonthier (mentioned in TFA) this morning where he explained about his formalization of the four color theorem.

      He actually used '2+2=4' as an example to explain the principle of reflection, one of the key mechanisms he uses to replace deduction by computation. He used type theory rather than set theory, though.

    38. Re:Critics Reaction... by nine-times · · Score: 1
      Oh yeah and 2+2=4 and that IS proven.

      Not really, more like it's posited, stipulated, accepted, and intuitively known. Or... do you have a proof? Do you have a proof for 1=1? In a sense, such proofs are possible, but a far bit more complex than you'd think.

    39. Re:Critics Reaction... by nine-times · · Score: 1

      Right... Having computers formulate a verify mathematical proofs that people can't understand is a little like having computers compose and then listen to music that people can't hear. What's the point?

    40. Re:Critics Reaction... by nine-times · · Score: 1
      If mathematical proofs were "nothing but a manner of convincing someone", how could it be verifiable by a computer?

      First, I think that was the point, that a proof really couldn't be "verified" by a computer because the nature of a proof is that it's proving something to humans.

      Second, computers are a mechanical (in the sense that electronics are still mechanical) means to executing "mathematical calculations" as have already been formulated, derived, and proven by human minds. The math that computers perform is math as we know it, not in the absolute sense, because that's how they were designed by us. Therefore, they should be able to "verify" that a formula is manipulated in ways that humans have programmed it to accept.

      In other words, computers perform mathematical calculation as they've been programmed to, but they cannot verify the validity of executing those calculations.

    41. Re:Critics Reaction... by Len+Budney · · Score: 5, Informative

      If you can't independently examine and verify your "proof" then how can it be considered proof of anything?

      That's easy. Speaking as a PhD mathematician, there's nothing disturbing at all about these computer proofs. They're examples in which a computer was programmed to generate a perfectly standard proof, except that it's extremely long.

      Checking the proof is not hard: it suffices to verify that the program emits only correct inferences. That's nothing more than a standard human-generated proof. In addition, a verifier can be coded by someone other than the original author, to check the validity of the inferences generated by the first program. The checker's algorithm can also be verified using a standard human proof, and would be used to confirm that a bug didn't result in an incorrect proof.

      Note that Gödel's incompleteness theorem has nothing to do with these programs: they don't generate all possible proofs. They only generate one specific type of proof per program. Each program is easy to verify.

      You could call the software correctness proofs "meta-proofs", but that's just being coy. They're perfectly legitimate proofs, and they are sufficient to prove the correctness of proofs generated by the program.

    42. Re:Critics Reaction... by maxwell+demon · · Score: 2, Interesting

      While you don't actually proof the human (you can't, of course), you do generally take steps to ensure that you don't rely on humans with faulty logic.

      For example, if some random student would come and say "I looked at the proof, and I think it is OK", then you wouldn't give it as much weight as if some mathematician who clearly has proven his profound use of logic in several papers goes through the same proof and says "everything is OK." And for at least some time, the computer program would be more like the random student, unless you can proof it works OK (of course this proof may be wrong as well, but it's another line of defense; 100% certainty is unfortunately not possible, even in math).

      Of course the situation is different if the program does find an error in the proof. Then you have a very narrow point to look at, and checking if the program is right in saying that step is wrong is probably not too difficult. Unfortunately this means bugs which cause wrong proofs to be judged as right will be much harder to detect than bugs which cause correct proofs to be judged wrong.

      Note that again this parallels the random student situation: If the random student comes and says "there's an error in the proof, you cannot follow blah from blubb", then checking if the student is right should be relatively easy (just look at the proof and see if that particular step is really wrong).

      --
      The Tao of math: The numbers you can count are not the real numbers.
    43. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      To paraphrase Bill Klem (a famous umpire): when asked whether a pitch was a ball or a strike, "It isn't anything until I call it".

      Or in terms geeks can understand,

      |pitch> = (|ball>+|strike>)/sqrt(2) .
    44. Re:Critics Reaction... by ortholattice · · Score: 1
      Here is a computer-verified proof that 2+2=4*. From that page: "The complete proof of 2 + 2 = 4 involves 2,062 subtheorems... These have a total of 21,969 steps -- this is how many steps you would have to examine if you wanted to verify the proof in complete detail all the way back to the axioms."

      *(Click on "2+2=4 Trivia" or add "#trivia" to URL - slashcode is changing "#" to "%23" so I took "#trivia" off of the URL)

    45. Re:Critics Reaction... by ortholattice · · Score: 1
      By definition of addition (remember, addition is not fundamental notion in the formal arithmetics, it's defined in terms of s-operator),

      To say "it's defined in terms of s-operator" is not a definition. If you want to define addition formally, it actually cannot be defined in terms that involve just the axioms of Peano arithmetic. You also need some set theory to do that. A formal definition of addition requires finite recursion, which in turn is also not a primitive notion (of set theory and certainly not of Peano arithmetic). A formal proof of just finite recursion from the basics of set theory is quite long.

      There is much more here than meets the eye, when you start talking about complete formal proofs.

    46. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      All your math are belong to us

    47. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      This is not an accurate description of the situation. A number of proofs have later been found to contain gaps, often depending on new understanding of fundamentals. (One might cite the parallel "axiom", and the completeness properties of the reals as two cases.) But formal logic wouldn't help sort these out.

      Nor is the finite group classification "unverifiable", although it is certainly a big job to do so.

    48. Re:Critics Reaction... by Listen+Up · · Score: 1

      As a Mathematician myself, I find it saddening that this entire forum of posts appears to be written purely by non-Mathematicians.

      To highlight one main point, there are multiple forms of Mathematical proof, axiomatic proof being the most widely used and cherished. All formal proofs are valid due to the previously and logically validated proofs on which they are based. Mathematics is a system of understanding and discovery that builds on itself. But, it is also important to understand that all formal Mathematical proof is disprovable. You cannot simply assert whatever you wish and try to convince people you are right. One counterexample, one logical error, one eror based on your results, etc. and your proof is invalid.

      What is the most important to understand is that without Mathematical proof, the world which you currently know would not exist, nor would any understanding of it. The universe is written Mathematically. The universe is not capricious and neither is Mathematics.

    49. Re:Critics Reaction... by Anonymous Coward · · Score: 1, Informative

      Actually there's at least two ways.

      The HOL group treats proofs as a data type. New instances of this type can only be constructed using a small set of inference rules. Therefore, if the system creates a proof, then you know that it has been created only by using these inference rules. Hence, trusting the inference rules is sufficient to trust whatever proofs are offered.

      A second way is the use of "reflection". That is, suppose that you had a "tautology checker" program which, given some proposition, returns true only if that statement is a mathematical tautology. And, suppose that you prove this program works correctly. Then, you can always trust the results of this program, and so any time it says that something is a tautology, you can believe it becuase of the proof you have done.

      There is an excellent paper by John Harrison that discusses these issues, which you can read here:
      http://www.cl.cam.ac.uk/users/jrh/papers/reflect.h tml

    50. Re:Critics Reaction... by tgibbs · · Score: 1

      Yes but a "correct mathematical proof" only establishes truth relative to the axiom system used. Because how will you ever prove that the axioms are true?

      Mathematical proofs are not actually statements of truth in the real world, but rather statements of contingency. They all ultimately reduce to the form, "If A, then B." Establishing truth in the real world means establishing by observation and experimentation that A is true.

    51. Re:Critics Reaction... by PDAllen · · Score: 3, Interesting

      It is very easy to produce a validator which correctly classifies valid and invalid proofs written in formal logic. It is very easy to prove that the validator does what it is meant to do.

      We don't know whether this abstract formal logic thing actually has any resemblance to the real world - that is not Goedel's theorem, which assumes logic to be valid and discusses potentially interesting frameworks for mathematics. Whether formal logic 'works' is simply something you have to believe, you cannot argue it, for the obvious reason. Whether you can use formal logic to demonstrate that your mathematical axioms are consistent is not obvious; Goedel's theorem states that in fact whenever your mathematical axioms are strong enough to produce interesting mathematics, you cannot demonstrate consistency.

      The reason why mathematicians do not like computer proofs (as much as normal proofs, anyway) and do not like computer validation (always) are:

      Computer proofs tend not to give any insight into why a statement is true. They simply check vast numbers of cases, when there might exist a simple argument which gives understanding. However, there is usually interesting mathematics involved in reducing the original problem to something which can be computer checked.

      It is not easy to produce a program which will verify a proof written by a normal person, in the same way that it is hard to write a program which can spot contradictions in any argument written in natural English.

      An argument written out in formal logic, although easy to verify for a computer, is generally much, much longer than the same argument written by a normal person, and even if you wanted to read the telephone-directory sized proof, the interesting ideas are so dispersed that you would gain no understanding from the proof.

      So, a computer verifier would only be useful when a proof is written in formal logic - which only a computer would do for a proof of any interesting statement. But the computer proof won't give a mathematician any understanding of why the statement is true, so the mathematician doesn't like it. Furthermore, because formal logic is so long-winded, it doesn't seem likely that a computer will ever be able to prove interesting statements by doing a simple bash out formal logic until it works approach. IMO, a computer program which can prove interesting mathematical statements in sensible amounts of time will be about as hard to write (and probably not too dissimilar to) a Turing-capable program.

    52. Re:Critics Reaction... by igny · · Score: 1

      When the algorithm is published, you can implement it from scratch on a different computer.

      Can you implement Windows from scratch? Can you guarantee there are no bugs?

      --
      In theory there is no difference between theory and practice. In practice there is. - Yogi Berra
    53. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      That's why you verify with a different architecture.

    54. Re:Critics Reaction... by igny · · Score: 1

      Do you have a proof for 1=1?

      If only I kept my homework from 1st grade...

      --
      In theory there is no difference between theory and practice. In practice there is. - Yogi Berra
    55. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      To say that their profession is being eliminated is laughable. You still need the mathematical background to develop programs that aid in the proof. And there seems to be a misconception on how computers help in the proof. You don't simply plug the "math problem" into some program and it generates the proof. In most cases you write a highly specialized program that verifies the numerous possibilities that need to be verified. As in the Four Colour Theorem, all the possible map configurations (I forget how many there roughly were) were generated and verified by the computer. But you still need to prove that your program is correct (i.e. it actually -DID- generate all the possibilities).

    56. Re:Critics Reaction... by TedCheshireAcad · · Score: 1

      But you're talking about simple algebraic manipulation. A machine could not, for example, prove the famous theorem of Lagrange - it would first have to invent the coset, then show that the cosets completely partition a group. It's not straight algebra.

      A machine could, however, symbolically verify homomorphism properties if it were so asked. But could it verify isomorphism? I don't think it could, it would probably need to enumerate the whole group structure, which is okay if we're talking about finite groups, but not the infinite ones.

      My $.02

    57. Re:Critics Reaction... by TedCheshireAcad · · Score: 2, Informative

      Do you have a proof for 1=1?

      = is an equivalence relation which is, by definition, reflexive.

    58. Re:Critics Reaction... by nine-times · · Score: 0, Flamebait
      Ummm... "by definition"? By whose definition? By a general consensus? By a common notion?

      Why can't I say, "!= is an equivalence relation which is, by definition, reflexive, and therefore 1!=1"? Because, conventionally, that's not what the != symbol is "defined" as, is it? So is convention a "proof"?

      Or did you consider that I wasn't asking about the conventional use of the "=" symbol?

    59. Re:Critics Reaction... by BritneySP2 · · Score: 1
      it is hard to write a program which can spot contradictions in any argument written in natural English

      Mathematical language is much more formalized than "natural English" is. A proof is analogous to (a description of) an algorithm, and it shouldn't be more difficult to validate a proof using a computer than it is to convert an algorithm to a program that can be actually run on a computer.

      It has been known for a century that mathematics can be formalized, and so it is remains a mystery why the question of automatic proof validation still generates a controversy.

    60. Re:Critics Reaction... by nine-times · · Score: 0, Troll

      If it's so simple, go ahead and come up with a proof now. Or has your understanding diminished since the 1st grade?

    61. Re:Critics Reaction... by WillWare · · Score: 1
      if the proof is too long to be checked, then it is flawed? WTF?

      Presumably the idea that a proof can be independently verified by somebody else (and for that matter, understood by another human) is the mathematical version of peer review. If a proof is not human-understandable, then it's not really a contribution to human knowledge.

      Remember the open-source argument that you wouldn't buy a car whose hood was welded shut. Even if you don't know squat about engines yourself, you can take it to a mechanic who does, and he can work on it. Given that the "open source" idea in software grew out of the "open inquiry" idea in academia, the parallel is more than accidental.

      A conspiracy theorist would fret about the day when computers know things we humans don't. But computers already process lots of information that humans don't see; this concealment is tolerable because the information is uninteresting. The scary thing is that "interesting" (say, life-or-death) information might be withheld by a computer, if only because it's simply incomprehensible to you or me.

      But the surgeon and the airline pilot are already in this position. We just have to trust their good intentions in using their many years of specialized training. We don't fear this situation because surgeons and pilots are human, and they work with human assistants. We expect that 99.9% of the time their motives will be comprehensible, and their work environment will be too info-porous to permit a big conspiracy. At the least, the number of successful conspiracies will be small.

      So there's a kind of giant-brained Frankenstein phobia happening here. What might resolve it would be to develop tools allowing mathematicians to break these proofs into reasonable chunks (maybe 1000 "obvious" steps), verify those independently, and then verify that those fit together to form a correct proof.

      --
      WWJD for a Klondike Bar?
    62. Re:Critics Reaction... by danila · · Score: 2, Insightful

      Your belief in the POWER OF THE HUMAN BRAIN is really funny. In reality you don't "truly knowing what your doing", no human does. It's just that we have evolved neat modules that "pretend" to know what we are doing. There are millions of people with serious brain damage. There are hundreds of millions of people with minor brain damage. There are billions with poorly working brains. When we think we know what we are doing, we are just executing our complex survival programs.

      Read The Man Who Mistook His Wife For A Hat or one of the many other amuzing (and amazing) books about our imperfect minds. If there can be a guy (apparently self-conscious, intelligent and normal), who can't tell the difference between his life-long female companion and a hat, how can you be sure that a particual mathematician can tell the difference between a correct step and a marginally and deceitfully incorrect? The answer - you can't. To err is human. Human verification is not inherently better than computer verification and in the future (as computers improve) it will gradually become worse.

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    63. Re:Critics Reaction... by PDAllen · · Score: 2, Interesting

      Mathematics _can be_ formalised. But no-one writes mathematics that way. First, because when a mathematician finds he has a proof the first thing on his mind is to publish ASAP to stop anyone else getting there first and taking all the credit, second because in practice writing in formal logic (or even mainly in formal logic) leads to long, boring, unclear proofs which do not enhance reputation the way a relatively short clear proof does. A boring proof is a sequence of equations and formal logic; this sort of thing is really only used when proving a little lemma that's almost obvious anyway. Most proofs will look something like the following (LaTeX) discussing a Frechet algebra F; B_n are the Banach algebras associated to the seminorms of F, the pi_n are projections from F to B_n, the d_n are the chain maps between the B_n:

      \begin{lemma} We may naturally identify continuous homomorphisms to $\mathbb C$ from $F$ and from the $B_n$, and so write
      \[\Delta(F,\mathbb C)=\bigcup_{n=1}^{\infty}\Delta(B_n,\mathbb C)\]
      \end{lemma}
      \begin{proof}
      If $\theta:B_n\rightarrow \mathbb C$ is a continuous homomorphism then so is $\theta\circ d_n:B_{n+1}\rightarrow \mathbb C$. Since $d_n$ has dense range, different $\theta$ give different $\theta\circ d_n$ and we may identify $\theta$ with $\theta\circ d_n$. Since also $\pi_n$ has dense range, we may identify $\theta$ with $\theta\circ \pi_n$. This allows us to write
      \[\Delta(F)\supseteq\bigcup_{n=1}^{\infty}\ Delta(B _n)\]

      and it remains only to show that there are no extra continuous homomorphisms. \\

      Suppose then that $T$ is a continuous homomorphism from $F$ to $\mathbb C$. In particular, $T$ is continuous at $0$, i.e. there is an open neighbourhood $U$ of $0$ such that $|T|1$ on $U$. This set is open in the inverse limit topology, i.e. is the intersection of the inverse limit space and an open set in the cross product of the $B_n$ with the product topology. $U$ may be assumed to be a set in a basis for the topology, so that it is the intersection of the $\pi_j^{-1}(U_j)$ for some $U_j$ open in $B_j$, up to some finite n.

      Since the $d_j$ are continuous, however, this intersection must contain $\pi_n^{-1}(V)$ for $V$ an open neighbourhood of 0 in $B_n$, the intersection of the inverse images of the $U_j$. \\

      We now show that $T=\theta\circ \pi_n$ for some $\theta\in\Delta(B_n)$, i.e. that $T(a)$ depends only on $a_n$, or that if $a_n=0$ then $T(a)=0$: if $a_n=0$, then $ka_n=0$ for all $k$, so $ka \in \pi_n^{-1}(V)$, and $|T(ka)|1$, for all $k$. But then $|T(a)|=0$ as required.
      \end{proof}

    64. Re:Critics Reaction... by Dan+D. · · Score: 1
      How long did it take humans to verify the proof that cold fusion is viable... I mean not viable... I mean viable? Or better example maybe how long did it take to verify that proof of fermat's last theorem? My number theory professor told us a story about a guy going in for his defence in Mathematics and in the process one of the committee started ignoring him and scribbling... by the end of the defence the committee member had established a much shorter and almost trivial proof of the guy's entire dissertation... I can only imagine... eesh... anyway, my point is that just because humans are in the loop won't ensure flawlessness...

      I think it comes down to the basic question, right? Just because someone shows you a long list of steps doesn't mean its true. The computer's steps are too small (which it does seem like it wouldn't be that hard to use a little pattern matching to come up with a few lemmas...) but theorem checking is an easier step, so feasibly maybe its worth starting to build trust in some applications... even as a first pass. I don't think humans should leave the loop... but its not like calculators ended human-kind's ability to calculate... it just crippled it dramatically :)

      --
      People who quote themselves bug the crap out of me -- Me.
    65. Re:Critics Reaction... by idlake · · Score: 1

      Yes computers can do things faster, but ever underestimate the power of truly knowing what your doing, which so far, a computer can't grasp at all, let alone do as well as the human mind.

      Finding a proof may require human imagination; verifying a proof should not. If it does, the proof is incomplete.

      But even multiple computers performing a verify isn't _truly_ a verification.

      Well, as far as I'm concerned, even multiple mathematicians "performing a verify" isn't truly a verification. Until a proof has been formalized and verified by a well-tested automated proof verifier, it remains an unverified proof sketch.

      After all, how long did the Pentium division bug go _unnoticed_???

      Well, Intel obviously failed to verify their design, probably because they exhibited the same hubris as you do. However, unlike erroneous mathematical proofs, which just languish unnoticed in mathematical journals for decades or centuries, when hardware companies fail to verify their designs, someone notices because they get wrong results.

    66. Re:Critics Reaction... by BritneySP2 · · Score: 2, Insightful
      long, boring, unclear proofs

      I do not suggest publishing only formalized proofs, or teaching mathemetics using formalized proofs. But if you have a "library" of formalized theorems (similar to having a library of subroutines), then it should be possible to translate your proof to a formal text that is not long, boring or unclear. And, in the end, you could add your new proof to the library!

      I believe that in time it will become the common practice, to publish both an "informal" and a formal proof.

      The realization of the striking similarity between proofs and algorithms will eventually make the complete formalization a natural part of the mathematical culture.

    67. Re:Critics Reaction... by idlake · · Score: 1

      Well, you have to verify that your proof checker is correct. Fortunately, that's a much easier problem because proof checkers are much simpler than complex mathematical proofs and because you can test proof checkers over a large number of known proofs to gain confidence in their correctness.

      You can attempt proving that your proof checker itself is correct. However, given that everything is at some point created and/or interpreted by humans, you can never have complete certainty. But a proof checker gives you a lot more confidence than a bunch of human experts.

    68. Re:Critics Reaction... by idlake · · Score: 1

      Your argument doesn't work because nothing is ultimately "verifiable"--there is always a non-zero probability of error. You can't completely verify the proof checker, and you can't completely verify the original proof.

      A proof checker, however, greatly lowers the probability of error because it automates a tedious and repetitive task. Furthermore, a proof checker can be tested with test cases, while a human cannot (humans don't work reproducibly).

      It's like accounting: you can do it by hand, but you generally get more reliable results from a computer.

    69. Re:Critics Reaction... by DM9290 · · Score: 1

      Program complexity has meant that all but the most trivial programs cannot be 'proven'.

      This statement is false in the general case. You are claiming that there is a set of "most trivial" computer programs which can be proven, but are impossible to make more complex by any amount without resulting in undefined behavior.

      For any given provable computer program, I can make a more complex version which is also provable.

      And I can further complicate that more complex version, also without introducing undefined behavior.

      This new program is NOT one of the "most trivial", because there is a more trivial program from which it is derived.

      What you are saying may be true in a a practical sense in regards to software developed for the sake of usage by human beings. (as people are not willing to invest the ridiculous amounts of money that proven software would cost).

      People are not even willing to invest the money to develop correct specifications let alone correct software.

      Without specifications, it is scientifically pointless to talk about software correctness. Because correctness without specifications is undefined.

      Your statement should be reworded:

      Specification AMBIGUITY has meant that all but the most trivial programs cannot be 'proven'. And where specifications are defined only after the fact, most non-trivial programs are found to be INCORRECT.

      --
      No one has a right to their *own* opinion. They have a right to the TRUTH.
    70. Re:Critics Reaction... by d34thm0nk3y · · Score: 1

      If you can't independently examine and verify your "proof" then how can it be considered proof of anything?

      Who cares, so long as it works.

    71. Re:Critics Reaction... by mesterha · · Score: 1

      In general, it is impossible to prove that such a 'formal logic validator' is correct since it is not possible to prove that an axiom system is correct inside that axiom system (one of Goedel's theorems). So if you would find a proof that your validator is correct, you'd have used reasoning techniques outside the logic of your validator, and do you believe those?

      Dealing with the consistency of the axioms is not the job of the validator. That is something for the mathematicians. They have to deal with it whether or not they use computers. So it's a red herring. The validators job is to confirm that the steps are legal in the formal system.

      --

      Chris Mesterharm
    72. Re:Critics Reaction... by PDAllen · · Score: 1

      I don't see any good reason to routinely publish formal proofs (by which I assume you mean computer-checkable) as well as a proof such as is commonly published. Yes, it would allow any mathematician to check the proof was correct without having to spend time reading and understanding the proof. But that's supposed to be the job of the reviewer, and the reviewer is seldom wrong. Also, if you are doing a bit of maths where it would be useful to use a result in some paper, then you generally want to be able to understand why the result is true, so you want to read the paper and understand the proof: it's in the right area, chances are there are ideas you can use yourself as well as the final result. Secondly, formal proofs are not just a bit longer than proofs as normally published. To look at the example I provided - I claimed that the identification between homomorphisms was natural. I actually didn't even refer to 'natural' in the proof - why? Because it should be obvious on reading the proof that I haven't had to play choice games, like choosing a vector space basis, to get my result, so that makes the identification natural. But I haven't ever tried to refer to the category of Frechet algebras and find myself a natural map (or whatever the category theory term is, I forget, it's not interesting anyway) to actually prove that it's a natural identification. Doing that - just that, not the rest of the proof - in formal logic would probably take several pages.

      Then, what do I mean by '$T$ is continuous at $0$'?

      Well:

      $\forall \epsilon > 0, (\exists \delta>0: (\forall x\in $F$, |x|\delta) |T(x)|\epsilon )$

      and that is a nice simple concept, easily expressed in formal logic. In fact, the whole proof is pretty simple stuff; you could read a bit of linear algebra, a bit of epsilon/delta analysis, and you'd know all you need to follow it.

      So, yes, you could build up a library of formal proofs of statements. But it would be much larger than a library of informal proofs, and it would not be of much use.

      I also don't see any justification for your last statement. Yes, some proofs give rise to useful algorithms, and to use the algorithm is roughly the same as writing the proof in formal logic. However, much as it may surprise you, mathematicians tend to notice those and give the algorithm in at least pseudo-code form in the paper. Most proofs don't give useful algorithms.

    73. Re:Critics Reaction... by Listen+Up · · Score: 1

      What I would also like to point out are arguments in this thread which are highly misdirected. You can create your own finite logical argument and use the rules of Mathematics to try and prove it true. Such exercises are generally given in college level Mathematics courses. But, those are just an exercises in using the logical rules of Mathematics, better known as informal proofs or convincing arguments. It is not definitive of Mathematics itself. A formal Mathematical proof of a something such as a universal Mathematical truth is something quite different.

    74. Re:Critics Reaction... by zbik · · Score: 1
      And any guesses how they even found this bug?? It was a human, not another buggy computer, that had to verify the data.

      Any guesses who was responsible for this bug? It was a stupid human who forgot to enter five values in the Pentium's lookup table (Matlab Digest). All computer errors can be traced to human errors, unless you think there are errors in nature. So if computer verification doesn't count because computers can make errors, then neither does human verification.

    75. Re:Critics Reaction... by zbik · · Score: 1
      We choose the axioms on which the proof is based. To paraphrase Bill Klem...

      The joke goes, three umpires are discussing balls and strikes. The first, an empiricist, says, "I call 'em as I see 'em." The second, a rationalist, replies, "I call 'em as they are." The third umpire, a constructivist of the Schroedinger school, spits on the ground and announces, "They ain't nothin' till I call 'em."

    76. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      I think you misunderstand the point of Gödels theorem. This theorem doesn't say, that there can't exist a machine that generates all possible proofs. In fact, it is a rather trivial matter to create a Turing machine that generates all legal proofs (and thereby all theorems) for, say, standard number theory or any other theory in some conventional logical system, in the sense, that the machine never stops (there's an infinite amount of theorems/proofs) but will eventually reach any possible theorem/proof. The tricky bit is not generating all proofs/theorems but rather, in finite time, answering the question: "Is this given proposition provable in the theory?". This is not decidable by a machine for any theories rich enough to support the natural numbers (the usual version with multiplication). By the way if a theorem is provable, the previously mentioned machine will print it out eventually. But if it isn't, the machine doesn't help us. This reminds that many here on Slashdot have written that Gödels theorem doesn't prevent a machine from proving theorems/doing mathematics but that it just displays some limitations in mathematics itself. This is not entirely true: Even the question "Is P provable in this theory" is undecidable even though clearly either P has a proof or it doesn't (it is true that P could be independent of the theory, but that just means there isn't a proof).
      Actually, it is Gödels theorem that prevents the following idea to solve the problem of deciding if a given proposition, P, is provable, from working: Take two machines, and configure one to look for a proof of P and the other to look for the negation of P. Isn't it then true then that one of them will eventually stop with a proof of either P or neg-P? In general no. This is only true for complete theories where we are guarenteed the existence of a proof or disproof. Gödel says that the only theories of the natural numbers that are complete are either very simple (for instance, without multiplication) or inconsistent (anything is provable).

    77. Re:Critics Reaction... by Len+Budney · · Score: 1

      I think you misunderstand the point of Gödels theorem.

      Nope.

      This theorem doesn't say, that there can't exist a machine that generates all possible proofs.

      That's correct. But Gödel's theorem applies if you build a machine that can prove anything: namely, proving that the machine actually works is exactly equivalent to the halting problem.

    78. Re:Critics Reaction... by khallow · · Score: 1
      But that's supposed to be the job of the reviewer, and the reviewer is seldom wrong.

      This statement is incorrect. Reviewers are routinely and often egregiously wrong. I would consider a proof that was viewed by three reviewers (typical standard) to be more correct than one that was dumped on the arxiv.org preprint server, but errors still get through. The real test is the inspection of the paper by the mathematical community, which for obscure papers still can be very incomplete. My point here is that there's a lot of uncaught error out there, and it has always been that way.

      So, yes, you could build up a library of formal proofs of statements. But it would be much larger than a library of informal proofs, and it would not be of much use.

      No, the library of formal proofs would be of use because all proofs contained therein would be correct to a degree that's impossible for all but the most commonly tested theorems to achieve. Frankly, it can take decades for some math to be considered correct, either because it's so difficult to verify or because there's so little talent/interest in the subject that few people bother to study it.

      Further, size really isn't the issue here (we have vast amounts of data storage at our disposal), but rather how much work it would take to generate the formal proof. I see real problems here. There are no standards for the structure of a formal proof, and hence no proof-checker available to the math community. Second, even if we had a rock-solid proof-checker, we wouldn't have adequate tools for translating informal papers to formal proof language. Basically, the software infrastructure just isn't there for constructing computer-verified math proofs.

    79. Re:Critics Reaction... by Flyboy+Connor · · Score: 1
      Can you implement Windows from scratch? Can you guarantee there are no bugs?

      No, but you don't need to implement it for the same OS.

    80. Re:Critics Reaction... by Zork+the+Almighty · · Score: 1

      Every proof rests upon axioms, and if we accept the axioms then we must accept a logically correct proof. However, we may also reject a proof on the basis of those axioms. For example, much of analysis rests upon the axiom of choice, a seemingly innocent statement with some absolutely bizarre consequences (refer to the link). In the past, some mathematicians would be inclined to reject a proof which used the axiom of choice, simply because they didn't want to accept the other consequences of the axiom. In this sense, mathematics is entirely subjective.

      --

      In Soviet America the banks rob you!
    81. Re:Critics Reaction... by PDAllen · · Score: 1

      There are something like a million papers published per year. Of those, maybe ten will later be found to be plain wrong, and another several hundred will have gaps which can't be easily filled. That's still less than a tenth of a percent. If I pick up some random paper I will probably find no errors in it. If I want to use results from it, I will read the proofs properly and check them anyway, because understanding the proof is often more helpful than understanding the result. But I will very seldom find myself wanting to use some result and discovering that the purported proof is not valid.

      There are standards for a formal proof - the basic sequence of formal logic statements - and these allow you to construct a proof checker easily. The problem, as you say, is translating your proof into formal logic; this is not something that a practising mathematician will be willing to do. It would be thoroughly boring, it would take weeks, and during those weeks while I muck about with logic that only a computer will ever read, some other guy is publishing the same result in a journal that doesn't need this silly extra proof, or working on my next result.

      It may become common to publish computer-checkable proofs with normal papers, but that will not happen until creating the computer-checkable proof does not take the mathematician significant extra time. Which will require a computer program that is a lot closer to genuine artificial intelligence than anything we have yet.

    82. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      Certainly not. It is trivial to build a machine that, provably, prints out all theorems of any theory given by a set of axioms (as long as the list of axioms is finite or at least recursively enumerable - otherwise it wouldn't even be possible to feed the axioms into the machine).

    83. Re:Critics Reaction... by Len+Budney · · Score: 1

      Certainly not. It is trivial to build a machine that, provably, prints out all theorems of any theory given by a set of axioms...

      That's not what I said. I'm talking about a machine that can prove any given theorem in bounded time or, if it is false, can prove the converse in bounded time. That machine can't by built, because if it were built it could solve the halting problem.

      People commonly cite the halting problem as evidence that theorem-provers can't work. But as I said originally, a program to solve the four-color theorem doesn't have anything to do with the halting problem: for starters, it only proves four-color theorems.

      In fact a four-color-theorem-prover is essentially what you've described: it generates only true statements, but also performs a search for the desired true statement (namely, the four-color theorem). In practice the search space is narrowed considerably by the designers of the program.

      You've made one error, though: this "trivial" machine you've described cannot "prove anything". You might think it can, but observe that it can't solve the halting problem. If I want to check a theorem, I start up your machine, and then wait. If it hasn't printed the theorem after one billion years, I still don't know whether the theorem is true or false. Similarly, if I want to solve the halting problem, I can run the program in question and see if it halts--but if it doesn't halt after a billion years, I'm still left wondering.

      More rigorously, given any time T, there is a theorem that will be emitted at time t > T. To see this, we construct the theorem as follows: Let machine M(t) print one true statement at time t, and assume that given any true statemen P, M(t)=P for some time t. Then the statement "M(1) and M(2) and ... and M(T)" will be printed at some time t > T. Therefore, your machine can't prove any given theorem in bounded time.

      You see, in simplest terms Gödel's theorem boils down to this: "The only general way to know whether a given program will halt is to run it and see."

    84. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      I don't believe I made an error. What I said wasn't wrong. The thing is, nowhere did I say the machine could *decide* any given proposition. I agree this is impossible and I even think I argued why it is impossible.
      But what can be made is a machine that will eventually emit any theorem. Thus, assume we somehow now that P is provable, after a finite amount of time the machine will determine that P is provable. For instance, assume you had an idea that a certain proposition was true but couldn't prove it. You could fire up the machine and if it was indeed true you would be guarenteed that the machine would eventually find a proof.
      But from using the machine you can never conclude that something doesn't have a proof just because the machine haven't emitted it after a certain amount of time.

      What I said (or at least tried to say) is that for any P which is provable, there exists T so that the machine will emit P after T operations. What I didn't say (but what it seems you think I said) was that there exists T so that for all provable P, the machine will have emitted P after T operations.

    85. Re:Critics Reaction... by Len+Budney · · Score: 1

      The thing is, nowhere did I say the machine could *decide* any given proposition. I agree this is impossible and I even think I argued why it is impossible.

      OK, back to the top: exactly what was your disagreement with me again?

      What I said (or at least tried to say) is that for any P which is provable, there exists T so that the machine will emit P after T operations.

      That's true, but completely uninteresting. You just said that although we can't solve the halting problem, given any program that halts there is a time T such that it does indeed halt by time T.

    86. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      I disagreed with:

      "Note that Gödel's incompleteness theorem has nothing to do with these programs: they don't generate all possible proofs. They only generate one specific type of proof per program. Each program is easy to verify."

      My point is that Gödels theorem doesn't prevent a program from generating all proofs as the above seems to imply.

    87. Re:Critics Reaction... by BritneySP2 · · Score: 1
      some proofs give rise to useful algorithms

      I was talking about a different thing - that there is a similarity between proofs and algorithms; since it is usually not a big problem to translate a well-understood algorithm into a ("formal") program, I expect a similar process of formalizing a proof to be not much more difficult.

      When "formalizing" an algorithm, you would normally use a high-level programming language rather than a machine code, and you would use libraries for, say, processing of text objects; the resulting program is usually not very big. Why would not you do something similar when formalizing a proof?

      There have been some efforts in that direction; see, for example, metamath.

    88. Re:Critics Reaction... by Len+Budney · · Score: 1
      My point is that Gödels theorem doesn't prevent a program from generating all proofs as the above seems to imply.

      You're quibbling. As I indicated in followups, a general-purpose theorem prover doesn't exist due to Gödel's theorem. Specific-purpose provers have nothing to do with Gödel's theorem.

    89. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      I think what happened is that I corrected something that wasn't correct in the original post (maybe your interpretation of it meant it was correct but according to my interpretation it wasn't correct), you misunderstood my correction and started stating things that are generally known to be true and that in no way contradicted anything I wrote - even trying to point out mistakes which are not there! And then you acuse me of quibbling?!

    90. Re:Critics Reaction... by Len+Budney · · Score: 1

      maybe your interpretation of it meant it was correct but according to my interpretation it wasn't correct

      Apology accepted, AC.

    91. Re:Critics Reaction... by Anonymous Coward · · Score: 0

      It wasn't meant as an apology but rather a summary of the discussion...

    92. Re:Critics Reaction... by khallow · · Score: 1
      There are something like a million papers published per year. Of those, maybe ten will later be found to be plain wrong, and another several hundred will have gaps which can't be easily filled. That's still less than a tenth of a percent. If I pick up some random paper I will probably find no errors in it. If I want to use results from it, I will read the proofs properly and check them anyway, because understanding the proof is often more helpful than understanding the result. But I will very seldom find myself wanting to use some result and discovering that the purported proof is not valid.

      Where in the world are you getting those numbers from? According to the American Mathematical Society's MathSciReview:

      Facts and Figures: 22506 items added in 2005; 1799 journals covered; links to 500526 original articles; 11304 active reviewers; 428094 authors indexed.
      That sounds like roughly 100,000 items total (including unrefereed articles) for the previous year (the review of articles always lags the publishing of articles by a year or so) and MathSciNet is pretty complete (at least for refereed mathematics papers). I think your published, refereed mathematics papers estimate is off by at least an order of magnitude.

      Also, I wager you are underestimating the number of papers in error. But even if you weren't, automated proof checking can achieve a lower error rate than 0.1%.

      It may become common to publish computer-checkable proofs with normal papers, but that will not happen until creating the computer-checkable proof does not take the mathematician significant extra time. Which will require a computer program that is a lot closer to genuine artificial intelligence than anything we have yet.

      This is absolutely correct. Still one has to consider the "extra time" of the reader. If you are right about error rates, then yes, it probably wouldn't make much sense to proof check until the time consumed is significantly shrunk.

    93. Re:Critics Reaction... by khallow · · Score: 1

      I should add however, that I don't see an automated proof checker replacing human readers. The proof checker (at least in the limited form as I imagine it) won't tell you whether a paper is interesting, relevant, or original, for example. Even a blatantly wrong paper could have a lot of value.

  3. Creativity by Daxx_61 · · Score: 5, Insightful

    Much of mathematics isn't just grunt power, there is also a lot of creative work going on there. Without humans to drive the computers doing the work in the right directions, it could take a long time before a computer would be able to get its proof - it simply doesn't know what it is looking for.

    I for one welcome our new robotic theorum proving overlords.

    --
    Quoth the server, "404."
    1. Re:Creativity by R.D.Olivaw · · Score: 4, Funny

      especially when we already know the answer it's looking for. 42

    2. Re:Creativity by Anonymous Coward · · Score: 0
      Precisely. The area of mathematics (even pointed to in the article) is called "experimental mathematics". You will only really see it in the area of discrete/finite mathematics. But the interesting stuff is still hard to do.

      For me it was useful in showing what was possible and what wasn't. We would run programs to find "things" in projective spaces. Even if we did find something you would still be stuck in the position of 1) seeing if it is new, 2) proving that it was new (subtle but different). (Think of the symmetry groups of objects. If it has a big group then you would find quadrillions of these things; smaller the group less of them there are hence harder to find).

      Generally exhaustive computer searches are impossible (you know, the amount of time before the sun goes medieval on our arses) for "interesting" problems . To make the computer searches feasible you need to think about the assumptions you need (starting configurations, symmetries etc) and then perform the search. The data you get back will give you some data points on where to do the next search. So "experimental mathematics".

    3. Re:Creativity by Zork+the+Almighty · · Score: 4, Insightful

      Without humans to drive the computers doing the work in the right directions, it could take a long time before a computer would be able to get its proof - it simply doesn't know what it is looking for.

      To some extent that's true, except in areas where human understanding has reduced mathematical proof to a mechanical process. For example, verifying algebraic identities, or even geometric proofs. A more advanced example is the Risch algorithm for elementary integration. It amounts to a proof that an integral either is or is not expressible in terms of elementary functions. Eventually we come to understand an area to such an extent that we can implement mechanical algorithms and move on. The proper role of the computer is to carry out these algorithms, so that we can use them to discover something else.

      --

      In Soviet America the banks rob you!
    4. Re:Creativity by call+-151 · · Score: 1
      I for one welcome our new robotic theorum proving overlords.


      You may find some agreement with some of Rutgers University math prof Doron Zeilberger'sopinions, particularly Opinion 36: Don't Ask: What Can The Computer do for ME?, But Rather: What CAN I do for the COMPUTER? where he suggests that eventually, computers may be doing the research in mathematics. There is a great line in there where he compares proving theorems by hand to jogging- yes, it may be reasonable, but a better way of getting someplace is to use a car/computer... If you get a chance to hear him speak, he is hilarious, BTW.

      --
      It's psychosomatic. You need a lobotomy. I'll get a saw.
    5. Re:Creativity by Anonymous Coward · · Score: 0

      Check out this classic paper by noted computer scientists/mathematicians Perlis, Lipton and de Millo for a unique perspective on the social processes underlying mathematical creations: http://uweb.txstate.edu/~mg43/CS5391/Papers/Formal Methods/socialprocessesproofs.pdf.

      Their basic thesis is that program verification is like a mathematical proof, a proof is not simply the formal verification of logical statements but instead involves social interaction between mathematicians, program verifications cannot be subjected to this social process because they are too dry, and hence, formal verification will never dominate software engineering.

    6. Re:Creativity by ameoba · · Score: 1

      Having done a bit of graduate study on the subject, let me tell you that using automated theorem proving tools still has a lot of room for problem-solving and creativity. As of now, there aren't yet theorem provers that can take the contents of basic algebra text (groups, rings, etc) and spit out those proofs without human intervention - there's still a trick to setting up the problems such that the computer can solve the problem in a feasable amount of time/memory.

      I'm not saying that automated reasoning tools aren't amazingly powerful & useful tools, in the right hands, just that they're not some magical source of all mathematics like the original poster suggested. Just as the calculator doesn't magically get rid of the need to know arithmetic, automated provers aren't going to do away with mathematicians any time soon.

      --
      my sig's at the bottom of the page.
    7. Re:Creativity by scotsalmon · · Score: 1

      There's also a distinct risk that if you let computers crunch at something long enough, you'll actually get proofs of wrong or at least misleading ideas. I've heard it noted that if Copernicus and Galileo had computers, we might still think of the Earth as the center of the universe, since the motions of the other celestial bodies with respect to the Earth can be described to good approximation if you keep making adjustments, adding additional epicycles, etc...if computers were available to solve that hard math problem, it might have taken longer to realize that it's much simpler not to think of the Earth as a fixed point after all.

      --
      101010, 222, 52, ...
  4. R. Daneel? Is that you? by Anonymous Coward · · Score: 0

    I for one welcome our new artificial über-geek overlords.

  5. If computers could write proofs... by John+Allsup · · Score: 4, Insightful

    Short, sweet, beautiful proofs of interesting and useful theorems, I would welcome them to do so with open arms.

    As a tool to produce vast quantities of precise logical porridge quickly, computers have no equal in today's world, yet that is not what real mathematical proofs should be about.

    Mathematical proofs should show short, clever ways of connecting otherwise disparate concepts that are only obvious in hindsight. This is where computers will always be weaker.

    --
    John_Chalisque
    1. Re:If computers could write proofs... by Dancin_Santa · · Score: 2, Insightful

      Mathematical proofs should show short, clever ways of connecting otherwise disparate concepts that are only obvious in hindsight. This is where computers will always be weaker.

      So you're saying that even a theoretical sufficiently advanced computer would be unable to match the logic and creativity of a human being? I think a simple brute force counter written in Mathematica (unlimited integer lengths) whose output was executed by a CPU would prove you wrong.

      Computers can separate wheat from chaff. That's what AI is all about. No, seamless human interaction is still a ways off, but as for number crunching, the ability to compare large, disparate sets, and logical "thinking", computers are vastly more well-suited to the task than humans in every respect.

    2. Re:If computers could write proofs... by Hideyoshi · · Score: 4, Funny
      Computers can separate wheat from chaff. That's what AI is all about.
      Which explains the glorious successes that subject has enjoyed in the last few decades ...
    3. Re:If computers could write proofs... by lisaparratt · · Score: 1

      A proof is a proof, whether it be long or short.

    4. Re:If computers could write proofs... by Anonymous Coward · · Score: 1

      Your rip on AI would be applauded except that AI is used in all sorts of everyday computing that it's amazing that it still gets a bad rap.

      Everything from load balancing to spam filtering to high-speed 3d graphics displaying uses AI to some extent. We used to call them expert systems, but you don't hear that term so much anymore because almost every system is an expert system of some kind.

    5. Re:If computers could write proofs... by shanen · · Score: 1
      Sometimes they do. In fact, some of the earliest theorem proving programs found new, short, and even elegant proofs of old theorems. However, after that the field didn't seem to advance very much for quite a while... Perhaps there have been some big breakthroughs lately? At least that's what this discussion seems to suggest.

      Actually, I was officially a math major for about a year (before my transition to the much easier computer science). Some parts of it were pretty simple, but the proofs always threw me. I'd spend a couple of pages proving what I thought was the crucial step, and old Professor Bichteler would tell me that it was obvious, but the critical part was over here in the line between these two other steps, where I'd incorrectly thought it was obvious... Also, I had a tendency to prove almost everything by contradiction, and the professors wanted direct proofs. Which leads back to the original topic, since many computerized theorem-proving systems have favored proof by contradiction.

      (However, the real reason I didn't become a better mathematician was probably the forced retirement of Professor Greenwood. He was a seriously great teacher, and I've always felt that a couple more classes with him would have made the difference...)

      --
      Freedom = (Meaningful - Coerced) Choice != (Speech | Beer^2), and sad sock puppets' bad mods avail them naught.
    6. Re:If computers could write proofs... by Sloppy · · Score: 2, Insightful
      Mathematical proofs should show short, clever ways of connecting otherwise disparate concepts that are only obvious in hindsight. This is where computers will always be weaker.
      Always be weaker? Some day, I think you'll eat those words.

      Getting a program working, is the first step. Making it optimize its output, is the next. I think you're going to see better proofs from computers.

      --
      As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
    7. Re:If computers could write proofs... by csrster · · Score: 1

      A theorem may be beautiful even if the proof is logical porridge. The Four Colour Theorem is surely a case in point.

    8. Re:If computers could write proofs... by slyguy135 · · Score: 1
      "This is where computers will always be weaker"

      I can hear Alan Turing turning in his grave.

    9. Re:If computers could write proofs... by Dulimano · · Score: 2, Interesting

      The problem with human-made proofs is that there can be gaps and even faults in them. Proofs with hundreds of pages are full of sentences starting with "It's easy to see that X.". Most often X is indeed obviously true, sometimes it is not.

      The goal of computer-aided theorem proving is to eliminate all these gaps. The human prover sketches her proof for the computer in a formal language. If some steps are missing, the computer calls her attention to these. When the long interactive process is finished, we have a proof that does not have any ""It's easy to see"s and "Obviously"s in it. At this point, another human can check the proof. But there is really no good reason to believe that this other human is more adept at checking it than the computer itself.

      The proof of the Four Color Theorem was recently formalized by Georges Gonthier in this way.

      From a philosophical point of view, many arguments can be made. But from a practical point of view: If I have to choose between believing a 300 pages long proof written in an informal language (Fermat's Last Theorem by Wiles) and a 1000 pages long proof written in a formal language, verified by a computer, I will choose the second one anytime.

    10. Re:If computers could write proofs... by TuringTest · · Score: 3, Insightful

      Current AI doesn't show creativity at all. In theorem proving, 90% of the required creativity is already present in the stated goal (the theorem), the other 10% is the heuristics programmed to guide the automatic search.

      --
      Singularity: a belief in the "God" idea with the "demiurge" relation inverted.
    11. Re:If computers could write proofs... by Flyboy+Connor · · Score: 1
      Mathematical proofs should show short, clever ways of connecting otherwise disparate concepts that are only obvious in hindsight.

      Tell it to Andrew Wiley.

    12. Re:If computers could write proofs... by Krakhan · · Score: 1

      A proof is a proof. What kind of a aproof? It's a proof. A proof is a proof. And when you have a good proof, it's because it's proven.

    13. Re:If computers could write proofs... by WhiteDragon · · Score: 1

      If I recall correctly from my discrete math class, the Four Color Theorem was proved with a relatively simple proof. The computer was not really used for the proof itself, but instead to exhaustively enumerate all the possible cases. It was a proof by exhaustion of the entire problem space.

      --
      Did you mount a military-grade, variable-focus MASER on an unlicensed artificial intelligence?
    14. Re:If computers could write proofs... by lisaparratt · · Score: 1

      And when you have a bad, inelegant proof, you still have a proof, because it's proven.

      Being short, elegant, etc. has no bearing on it's provenness, and little bearing on it's utility for the majority of users.

    15. Re:If computers could write proofs... by Dulimano · · Score: 1

      There are now three different proofs of the Theorem. All work by by exhaustion of a very large problem space. The original '77 proof is by Appel and Haken. A second one is by Seymour et al. The third one by Georges Gonthier is very new. It's the really interesting one in this discussion, because it is a totally formalized proof, built with the help of the Coq mechanical theorem prover.

      The point is, IF you believe that the Coq software works correctly, then you can now be SURE about the Four Color Theorem. Before Gonthier, you had to proof-check hudreds of pages, and debug and run some quite complicated programs to validate the proof. Seymour et al. did their own proof partly because this was easier than verifying Appel and Haken's very complicated one.

      There is a very nice article about this here.

    16. Re:If computers could write proofs... by Dulimano · · Score: 1

      We live in an era where really interesting theorems often have many hundred or thousand pages proofs. (Last Fermat by Wiles, Kepler by Hales, The Classification of Simple Groups). It's unrealistic to believe that there are no gaps in such proofs. All my three example theorems had gaps, some quite serious. A huge gap in the proof of the Classification of Simple Groups was only found after about ten years. Serre, the most prominent group theorist still doesn't believe that the theorem is really proved.

      So, it's unrealistic to believe that there are no gaps in very long proofs UNLESS the proofs are totally formalized. My prediction is that in 20 years, only such formalized proofs will be accepted in journals on pure mathematics.

    17. Re:If computers could write proofs... by igny · · Score: 1

      I think you're going to see better proofs from computers.

      Someday a human will come up with a 20 page correct proof of a 4-color theorem.

      --
      In theory there is no difference between theory and practice. In practice there is. - Yogi Berra
    18. Re:If computers could write proofs... by igny · · Score: 1

      Wiley is a counterexample, which proves the statement. On the other hand, see Grigori Perelman...

      --
      In theory there is no difference between theory and practice. In practice there is. - Yogi Berra
    19. Re:If computers could write proofs... by WhiteDragon · · Score: 1

      Thank you. This is quite interesting to me, and I am almost 100% sure that the only proof I knew of was the Appel and Haken one then. I remember seeing a video on it, and it was all ancient computer tech.

      --
      Did you mount a military-grade, variable-focus MASER on an unlicensed artificial intelligence?
    20. Re:If computers could write proofs... by danila · · Score: 1

      The average human doesn't show any creativity either. So what?

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    21. Re:If computers could write proofs... by MyLongNickName · · Score: 1

      Then grab a shovel and let him out!

      --
      See my journal for slashdot ID's by year. Mine created in 2005. http://slashdot.org/journal/289875/slashdot-ids-by-year
    22. Re:If computers could write proofs... by cpeterso · · Score: 1


      As a tool to produce vast quantities of precise logical porridge quickly, Slashdot has no equal in today's world.

    23. Re:If computers could write proofs... by Flyboy+Connor · · Score: 1
      Wiley is a counterexample, which proves the statement

      You are obviously no mathematician, if you think a counterexample proves a statement...

      But I agree mathematics is at its most beautiful when proofs are elegant. Unfortunately, many of the elegant proofs are already discovered; it is the area of inelegant proofs that is still wide open...

    24. Re:If computers could write proofs... by TuringTest · · Score: 1

      There are humans that show creativity, but there aren't computers that show creativity. Not yet.

      So instances of "computer creativity" like theorem proving are really hidden instances of a creative human.

      --
      Singularity: a belief in the "God" idea with the "demiurge" relation inverted.
  6. If there are no proofs by willmeister · · Score: 0

    then my brother won't have to suffer through what I had to in High School Geometry. Long Live Proofs

    1. Re:If there are no proofs by arodland · · Score: 2, Interesting

      You mean... thinking?

      Geometry wasn't the most useful of my high school math classes, but it was the most fun, because we all worked together to come up with proofs, showing that those lousy formulas we had to memorize all had their root in Euclid.

      Similarly, anyone who wants to go anywhere with calculus should at least try to understand the proof of the existence of limits, at least for a few minutes, because that's what makes calculus something other than voodoo.

  7. Seems simpler to prove proffs-by-computer by Anonymous Coward · · Score: 3, Insightful
    Simply prove the program correct; and all its outputs will be correct?

    To do that.... well, just make sure the program was designed by a correct computer.

    1. Re:Seems simpler to prove proffs-by-computer by rxmd · · Score: 5, Informative
      Three major obstacles with this approach (which has been tried BTW):
      • Logical problems with proofs for correctness. For example, it has been proven that no program can prove itself correct.
      • Correctness proofs are hard to do and incredibly tedious. Have you ever tried it? And no, you can't have a program do them, because you'd have to prove this program correct, which sends you right back to square #1.
      • You'd have to prove all sorts of other factors correct, including the operating system and hardware your program is running on. This leads to another set of interesting problems, including that "correct hardware" is useful only as a theoretical concept. What's a "correct computer" if there's a small probability that bits will spontaneously flip in memory, for example?
      In short: while it might seem elegant to prove the prover, then have everything else proved by this prover, this approach has little value in practice.
      --
      As a state gets corrupt, its laws multiply; the most corrupt states have the most numerous laws. (Tacitus, Annales 3:27)
    2. Re:Seems simpler to prove proffs-by-computer by Anonymous Coward · · Score: 0

      *Correctness proofs are hard to do and incredibly tedious. Have you ever tried it? And no, you can't have a program do them, because you'd have to prove this program correct, which sends you right back to square #1.*

      any formula is a program of it's own.

    3. Re:Seems simpler to prove proffs-by-computer by darkov · · Score: 4, Interesting

      I agree with (1), I believe Godel had a hand in that one.

      With (2), the program can reduce the tedium of proving the original proof in some cases. That's what computers are good at and are better at than humans. Proving the program may well be much easier. I would think that's why the researchers in the article used computers in the first place. If you program in C++ you will have a problem, but a functional or logic language program is straight-forward to prove (PROLOG programs are essentially the execution of a proof).

      With (3) you could show by running it on different hardware and software that the platforms did not affect the result by a huge probability. If you don't like the 'probability' bit, who says there isn't a human trait or gene that causes any human to get a proof wrong? Humans are imperfect too, but if enough of them agree, and they are qualified, then we agree that what they agree on is true. This is the same situation as the potentially flawed platforms problem.

    4. Re:Seems simpler to prove proffs-by-computer by Anonymous Coward · · Score: 0

      Doesn't this run into the Halting Problem?

    5. Re:Seems simpler to prove proffs-by-computer by adepali · · Score: 1

      Actually what has been proven is that no program can prove any program correct. Giving the program itself as input is part of the proof.

    6. Re:Seems simpler to prove proffs-by-computer by kabocox · · Score: 1

      Three major obstacles with this approach (which has been tried BTW):

      * Logical problems with proofs for correctness. For example, it has been proven that no program can prove itself correct.

      In short: while it might seem elegant to prove the prover, then have everything else proved by this prover, this approach has little value in practice.

      You'd have to prove all sorts of other factors correct, including the operating system and hardware your program is running on. This leads to another set of interesting problems, including that "correct hardware" is useful only as a theoretical concept. What's a "correct computer" if there's a small probability that bits will spontaneously flip in memory, for example?


      What's the difference between a human trying to prove a concept and a computer? Do I have to prove that I'm a "correct" human before I'm allowed to prove a math theorm? If so, I'm sorry we have to separate out math by folks that didn't proof themselves to be correct humans in a correct human biologic systems.

    7. Re:Seems simpler to prove proffs-by-computer by po8 · · Score: 1

      Let's be clear. What Godel showed is roughly that no program can certify that every correct program handed to it is correct, unless it also certifies that some incorrect programs are correct (i.e. it is unsound). The standard statement of this is that any sufficiently powerful logical system is either unsound or undecidable.

      What this means in practice is that for any sound correctness-proving program, if you're willing to wait only n seconds to finish, there are input programs on which it will not terminate before you lose patience. This is true for any n you choose.

      The good news is that a given prover can normally be proven sound (but not complete) using itself. I think the confusion WRT Godel's Theorem is that the theorem proceeds by showing that for any given prover P there is a logical statement Q that is true but cannot be proven by P. This in turn is used to show the incompleteness of P. But P might still be able prove a lot of stuff, including everything you would care to know, and perhaps including the logical statement "P is sound".

    8. Re:Seems simpler to prove proffs-by-computer by ortholattice · · Score: 1
      "In short: while it might seem elegant to prove the prover, then have everything else proved by this prover, this approach has little value in practice."

      Here is a 300-line Python program that can verify the formal proof of any theorem (that can be proved from ZFC set theory axioms, which is essentially all of mathematics). So all you have to do is prove the correctness of these 300 lines, and the job is done. See us.metamath.org home page for more information on this program.

    9. Re:Seems simpler to prove proffs-by-computer by BritneySP2 · · Score: 1

      This all has purely theoretical interest. We trust computers doing much more important things than proving theorems. You are arguing with the obvious. Of course computers are more efficient than humans in (formally) validating proofs, and of course we can and should trust (well-tested) programs.

    10. Re:Seems simpler to prove proffs-by-computer by Anonymous Coward · · Score: 1, Insightful

      If all you need is a really small probability of being wrong, you may not need a proof. For example, if I wanted to show that (x+y)^2 - (x-y)^2 = 4xy, I could randomly choose say 10^8 different pairs of integers (x,y) and verify equality for every pair.

      A proof, OTOH, will show you (to a high degree of probability, since humans are fallible) not only that they are equal, but also *why* they are equal. *That* is the importance of proof!

      Re fallibility: About 1/3 of the mathematical papers that I've refereed have contained a fatal flaw. Just because someone asserts that they have a proof doesn't make it so.

  8. Does it really work? by janek78 · · Score: 1, Funny

    Computer generated proofs really do seem like a real time saver. Provided that they work. Now, if we could only prove that... Let me think, how about building this atomic superpowered robotic monster to prove that computer generated proofs work? Or perhaps we could use those computers to prove it themselves!

    1. Re:Does it really work? by lisaparratt · · Score: 1

      Ah, I see you've come across the Z method then?

      I hate prooving algorithms >_

    2. Re:Does it really work? by Anonymous Coward · · Score: 0

      Computer, prove thyself!

  9. The Economist discussing math.... by Anonymous Coward · · Score: 0
    is like Microsoft discussing computer security.

    If it were a math journal publishing this paper it might have some credibility.

    But considering the source, it's just so a bunch of MBAs can feel smarter than PhD Mathemeticians for a while.

  10. Maths and computers? Who'd have thought by Anonymous Coward · · Score: 0

    Wow, you mean computer's can do maths? Maybe now someone can include a calculator with my favourite shipping of XP, or... maybe we could use math in programming?!! omfgbbq..

    1. Re:Maths and computers? Who'd have thought by Anonymous Coward · · Score: 0

      Better than you can 'do' English. The rules of possesion and pluralization aren't that hard to learn. Access to the internet should be only allowed after passing a basic grammar and spelling test.

  11. Uh, I doubt it. by Anonymous Coward · · Score: 1, Insightful

    Since you're going to need a human to write the proof of correctness for the program that wrote the other proofs, aren't you now?

    Anyway, the entire point of a proof is to be read by humans. This isn't like, say, a computer program, where the point of the proof. A mathematical proof is something humans create in order to convince other humans of things beyond all doubt. The four color theorem proof was pretty closely watched; I guarantee you if you just go up to someone and say "statement [i]blah[/i] because my expert system verifies it to be the case" there is going to be some fucking doubt still there.

    1. Re:Uh, I doubt it. by g1t>>v · · Score: 1

      And what if you go up to someone and say "statement blah because here's a (very large) proof that my expert system generated, but which can be verified with a simple program which is just a few pages long"? Remember that *finding* a proof is hard (and hence requires human creativity / AI stuff) but *checking* that a proof is correct is easy (just a bit tedious when the proof is very large, and whom better to trust to do this job than a computer)?

  12. Here's a good theorem prover by carnivore302 · · Score: 4, Informative

    In the past, I've used the HOL Theorem Prover. It's a nice toy to play with if want to get started in this area.

    --
    Please login to access my lawn
    1. Re:Here's a good theorem prover by Anonymous Coward · · Score: 0

      and HOL is open source

    2. Re:Here's a good theorem prover by ameoba · · Score: 1

      Two other systems are Otter a resolution-based theorem prover and the Boyer-Moore Theorem Prover - the classic Lisp-based inductive reasoning tool. Honestly, I find the inference-based reasoning of Otter to be a lot more straighforward and intuitive.

      --
      my sig's at the bottom of the page.
    3. Re:Here's a good theorem prover by Anonymous Coward · · Score: 1, Informative

      You might also want to take a look at Twelf.

  13. The best math is always elegant. by Pants75 · · Score: 5, Interesting
    That's what my math teacher always said, back in school. I'm sure he would extend that statement to include proofs, given that they are also just math.

    What about Fermats last theorem? Fermat wrote in the margin of his note book that he had a proof, but it was too large to fit there, so he'll write it on the next page. Trouble was, the next page was missing from the book.

    The modern proof for FLT took hundreds of pages of dense math and went through some math concepts that AFAIK hadn't even been invented in Fermats time.

    What was Fermats proof (if it existed)? It would surely have been far more elegant than the modern version.

    That doesn't make the modern version wrong, just less pure, I feel.

    The problem with modern computer aided proofs is they allow the proof to become unwieldy and overly verbose, compared to what it would have to be if just a human produced it.

    Such is progress I guess.

    1. Re:The best math is always elegant. by wwahammy · · Score: 1

      A non-existent or incorrect proof can be very elegant I suppose.

    2. Re:The best math is always elegant. by Craigj0 · · Score: 3, Funny

      Perhaps his proof was flawed and he realised it so he ripped the last page out?

    3. Re:The best math is always elegant. by Pants75 · · Score: 1
      Yeah, thats always been a big assumption about Fermat.

      I'd love someone who could test it to get hold of a copy though.

      Tantalising.

    4. Re:The best math is always elegant. by PaschalNee · · Score: 4, Insightful
      For every complex problem there is an answer that is clear, simple, and wrong. H. L. Mencken
    5. Re:The best math is always elegant. by RidiculousPie · · Score: 1

      The consensus of the mathematics professors I have spoken to is that:
      Gauss was a more talented mathematician that Fermat, and if he didn't see the solution then it was not possible with the mathematics that Fermat had.

      --
      ah, mod points ... now where is my crack?
    6. Re:The best math is always elegant. by Anonymous Coward · · Score: 1, Informative

      Yeah, it's definitely generally believed that Fermat was full of shit. For one thing, he later published a proof for x^4+y^4=z^4 does not exist. If he had a proof for the generalized form that he claimed to have, why would he bother publishing this more specific, far less interesting, proof?

    7. Re:The best math is always elegant. by Anonymous Coward · · Score: 1, Informative

      full of shit is a bit of an exageration

      the works we have from fermat are ones that he never intended to be published

      imo the most likely explanation is that he found a false proof and later realised it was false but for some reason did not destroy that one note.

    8. Re:The best math is always elegant. by Anonymous Coward · · Score: 0

      It is widely thought though that he actually didn't have a proof, and if he did, seeing how difficult the actual proof was, his was probably wrong. As pointed out by a math teacher I know, Fermat was the kind of guy who thought each and every proof he did was "better, remarkable, more elegant". Admittedly, it was indeed the case for many proofs he rewrote, but this one seems dubious in many people's opinion.

    9. Re:The best math is always elegant. by Bazzalisk · · Score: 3, Informative

      In fact Ramanujan thought he had a proof, which would have been doable using only things known in Fermat's day and was short elegant and pretty.

      Unfortunately, as Hardy pointed out, that proof assumed that all Quadratic extensions of the rational numbers are Unique Factorisation domains - which isn't true ;-/

      It seems very likely that Fermat's proof was probably of a very similar sort.

      --
      James P. Barrett
    10. Re:The best math is always elegant. by kisak · · Score: 5, Informative
      What was Fermats proof (if it existed)? It would surely have been far more elegant than the modern version. That doesn't make the modern version wrong, just less pure, I feel.

      Mathematicians think they know what Fermat thought was the "proof" that he could not fit in the margin, since Fermat used a similar strategy for another problem. Euler was the one who used Fermat's strategy on Fermat's last theorem explicitly, and showed that it did not give a full proof as Fermat had hoped. It might be that Fermat himself tried and then gave up, or that he was happy to have "solved it" and looked for other things to prove.

      I think you (and most people) misunderstand the reason Fermat's last theorem has such a central place in math history. But first lets discuss the reason why the problem became so well known; it is because it is such an easy problem to state and to understand, still no one has been able to use "simple" math to prove it. Even Fermat himself thought the problem should be fairly straigth forward to solve, and it has made generations of people with curiosity for math look for proofs and even thinking they have found one. It is also a problem some of the greatest minds of math did not manage to solve. Fermat, Euler, Lagrange, Gauss, Abel, Riemann, etc have all had a try and did not solve it. Which math wanna-be wouldn't want to solve something this group of people did not manage?

      Now, even though this has made Fermat's problem something that has created a lot of publicity, the number one reason Fermat's problem has been important, is because of all the beautiful maths that have been discovered by mathematicians trying to solve it. Fermat's theorem in itself is not interesting. It is not like the Riemann hypothesis, which if proven to be false, will make much of modern maths not true or at least force mathematicians to look for new proofs. This is because you can prove much interesting stuff if you assume the Riemann's hypothesis is true, problem is of course, this is not yet proven. If Fermat's theorem was been shown to be not true, that would have been suprising, but would not made large parts of maths collapse.

      So, the modern proof of Fermat's theorem is the end of a long journey which has lead to some very deep mathematical knowledge, and in a way, Wiles' proof is much more interesting in its own right than that it also proofs that Fermat was right in his guess. A "simple" proof (watch out when mathematicians use the word simple or trivial) of Fermat's problem would give undeniable bragging rights, since you could say you solved a problem Gauss couldn't solve with the maths Gauss knew. But again, it probably would be more of a huge accomplishment for one person than a huge breakthrough in maths.

      A last comment; the reason Wiles' proof is long is not because math is verbose, far from it . It is because Wiles is able to connect what would seem to be two unconnected branches of mathematics, showing that problems in one of the branches can be restated as problems in the other. This is not something you do in a few pages. And the importance of it becomse clear, if you consider that what can be an unsolveable problem in the one branch of maths might be reformulated as a solveable problem in the other. Math is always about trying to find ways to solve something as simply as possible. Not something computers is very good at, so no Abel prize to Big Blue for a while I think.

      --

      --- guns don't kill people, people with guns kill people ---

    11. Re:The best math is always elegant. by daniel_mcl · · Score: 1

      Whatever Fermat's proof was, we can be pretty sure that it was wrong. He was in the habit of making a lot of guesses like this and sometimes claiming to have a proof when he didn't (i.e. when he said he'd proved something that wasn't true).

      --
      I used to read Caltizzle. I was a lot cooler than you.
    12. Re:The best math is always elegant. by Have+Blue · · Score: 1

      Until you can precisely define and quantify elegance, that's not a useful rule (for one thing, "elegant" does not always mean "small"). What makes you think the modern proof is any larger than Fermat's would have been? Maybe the "proof the margin was too small to contain" was an extremely simplified outline that would have had to be expanded to something equivalent to the modern proof before it was sound.

    13. Re:The best math is always elegant. by quisph · · Score: 1
      The problem with modern computer aided proofs is they allow the proof to become unwieldy and overly verbose, compared to what it would have to be if just a human produced it.
      Nonexistent?
    14. Re:The best math is always elegant. by greatmazinger · · Score: 1

      It also probably means that Fermat was mistaken in thinking that he had a proof. Also "purity" is a matter of religion. Proof is proof, computer aided or not.

    15. Re:The best math is always elegant. by hawkfish · · Score: 1

      A witty remark is not an argument. - Voltaire

      --
      You will not drink with us, but you would taste our steel? - Walter Matthau, The Pirates
    16. Re:The best math is always elegant. by Hao+Wu · · Score: 1
      What about Fermats last theorem? Fermat wrote in the margin of his note book that he had a proof, but it was too large to fit there, so he'll write it on the next page. Trouble was, the next page was missing from the book.

      Did Fermat have a sense of humor? At work I often say "yeah, I'll get right on that" when there's a task that I don't even plan to attempt...

      --
      I suggest you read Slashdot
  14. Computer _aided_ proofs by irexe · · Score: 4, Insightful

    Computer proofs, like the graph color proof, are not proofs that are completely generated by a computer. The computer is merely used to brute force a fairly large number of 'special' cases which together account for all cases. The construction of the proofing method is and will remain human work, lest we create AI that matches our own I.In short, they are computer aided proofs only.

    Further and more importantly, at this point we do not have and are not likely to have a machine that can prove any provable theorem (and fyi, not all truths in mathematics are provable!).

    1. Re:Computer _aided_ proofs by g1t>>v · · Score: 2, Informative

      Then you'd better check your facts ... there must be dozens (if not hundreds---erhhh, speaking about checking ones facts :-) ) of systems in which mathematical theorems are routinely proved (HOL, PVS, Coq, Mizar to name just a few)!

    2. Re:Computer _aided_ proofs by ivano · · Score: 1
      Yeah...someone get it!

      Ciao

    3. Re:Computer _aided_ proofs by vanicat · · Score: 1

      Then you'd better check your facts ... there must be dozens (if not hundreds---erhhh, speaking about checking ones facts :-) ) of systems in which mathematical theorems are routinely proved (HOL, PVS, Coq, Mizar to name just a few)!


      Then you'd better check your facts. At least coq, and probably the other too, are proof assistant, and that mean that the help you to wrote your proof, and check that it is correct. But most proof are still mainly done by human.

      The only completly automatic prover I know of is prolog, and prolog is not able to soundly use the "not".

      To find a proof of a given formula is generaly undicedable, and when you are sure that one exist, you generaly need an exponantial search to find it. Human are still needed to find the good direction in the search.
    4. Re:Computer _aided_ proofs by HuguesT · · Score: 1

      Yes, but not new ones !

      so-called theorem-proving systems are able to *check* human proofs for logic mistakes or sometimes to generate proofs for small known problem.

      However AFAIK no new interesting proof of an open problem has been given entirely by computer yet. I.e, input the statement of the problem in some formal language, let the computer run and produce a proof of the statement.

      The 4-colour theorem is not a counter-example. All the computer did was run through a givent list of configurations and check that some given properties were true for them. The checking was hard to do for humans because is was arduous and repetitive, but in this instance the computer program was not asked to show any creativity.

    5. Re:Computer _aided_ proofs by mesterha · · Score: 2, Insightful

      (and fyi, not all truths in mathematics are provable!)

      This is wrong. It is based on a misunderstanding of Godel's proof that has been popularized by various authors.

      All truths in mathematics are provable. However, assuming our system of mathematical axioms is consistent, there are some statements that are neither true or false. These statements have not been determined by the axioms. Furthermore, for any computable set of mathematical axioms we choose, there are always some statements which are undecided. Godel proved this by coming up with a technique that always generated one of these undecided statements.

      --

      Chris Mesterharm
  15. Re:Godel/Turing/Cohen... by willmeister · · Score: 2, Informative

    I have no doubt that in 50 years (given current progress), creativity as we know it will be commonly implemented in advanced computers. Your brain is nothing more than a biologically advanced computer, complete with binary nerve signals and the works.

    Why can't human brain functions be copied and improved upon in circuitry, other than the currently prohibitive costs involved, and our failure to accurately determine the exact neuron mapping of anyone's brain. Even the dynamic neuron connections could be potentially emulated or mimiced by a computer.

  16. very long proofs by bkubi · · Score: 0

    can lead to different results than shorter ones, but both are correct. And this inherent failure of mathematics can be used to create new mathematics. Anyone interested, read my favorite scince fiction author: Greg Egan - Luminous I really like the book.

    1. Re:very long proofs by StrawberryFrog · · Score: 0

      can lead to different results than shorter ones, but both are correct.

      That to me is an extraordinary claim, and I'd like to see proof of it.

      Anyone interested, read my favorite scince fiction author:

      Much as I like Greg Egan, fictoin is never a proof of anything. Because it's, you know, not actual.

      --

      My Karma: ran over your Dogma
      StrawberryFrog

  17. Are computer-aided proofs really proof? by Mattb90 · · Score: 3, Insightful

    During my preparation for my interview to study Mathematics at Cambridge last year, one of the discussion topics that came up was computer-aided proof. Between the interview-experienced teacher, a school colleague who was also applying and myself, we came to the idea that computer-aided proof might not be proof at all, because proof for Mathematicans is the ability to reproduce the workings by yourself - it might take a very long time, but the idea should be that a human could dervive them in order for them to be considered true proofs of human concepts. Whether many in the Mathematical community in England take this view, I won't know until the end of the year when I hope to start my course - but based on this debate, it wouldn't surprise me if quite a few did.

    --
    Mattb90
    Editor, allaboutgames.co.uk
    1. Re:Are computer-aided proofs really proof? by Anonymous Coward · · Score: 0
      my preparation for my interview to study Mathematics at Cambridge ...Whether many in the Mathematical community in England take this view, I won't know until the end of the year when I hope to start my course

      Note that Cambridge is one of the leading places for computer-aided proofs.

    2. Re:Are computer-aided proofs really proof? by ockegheim · · Score: 1

      Accepting a computer-generated proof too complex for one mathematician to reproduce would require an element of faith. A non-mathematician like me must have faith in the existing system of peer review. Whether mathematicians would be comfortable in a quasi-theological role is a different matter.

      --
      I’m old enough to remember 16K of memory being described as “whopping”
    3. Re:Are computer-aided proofs really proof? by Dony · · Score: 1

      Well, I don't think it's necessary for a human to verify the proof. One might be able to verify a proof with the aid of a computer, for instance, using software that we haven't developed yet. The important thing is that for a conjecture to be a proof, it must be verifyable. Otherwise, it's just a hypothesis or a possibility. If there's a flaw in the way the program executed the proof for instance, it might show a theorem as having been "proven" when in fact it has not. Unless someone (and I think this can be done with the aid of a computer as well) can verify the results, I don't think we can confidently call a theorem "proven."

      --
      Machiavelli, a graphic novel
    4. Re:Are computer-aided proofs really proof? by Anonymous Coward · · Score: 0

      Uh-huh... and, to a factory worker, a "car" isn't a "car" unless it can be built by hand by a person. Get over yourself. You'll be outsourced along with the rest of us.

  18. No progress without understanding by Freaky+Spook · · Score: 5, Insightful

    I remember how much I hated learning alegebra, trig, calculus etc & how much the theory sucked, I never saw any point to it & loved it when I discovered my TI-83 could do pretty much everything.

    Although I discovered easier ways to do the arithmatic, I still knew the underlying theory of the equations & what the numbers were actually doing, not just what a computer was telling me.

    Students should learn this, they are the basic building blocks of a science that dictates pretty much everything on this planet & although they won't have a use for everything they are taught they will have enough knowledge to "problem solve" which is what most of high school maths is designed to do, it trains our brains to think logically & be able to work out complex problems.

    How are people going to be able to further phsyics, medicine, biology if they get into their respective tertiary courses without understanding the basic principals of all science & have to learn it all over again??

    Or what about when computers just won't work & things have to be done by hand??

    Its fair to integrate comuters into maths but not at the expense of the theory that makes us understand how things work, we should not put all our faith in technology just because its the easy thing to do.

  19. What about feigenbaum constant? by Anonymous Coward · · Score: 0

    Doesn't the story go that the Feigenbaum constant was discovered because he moved away from computers, not onto them? Or was that Lotfi Zadeh and fuzzy logic?

    1. Re:What about feigenbaum constant? by Zork+the+Almighty · · Score: 2, Interesting

      I believe that Feigenbaum's constant was discovered with the aid of a programmable pocket calculator. He noticed something, and used the computer to check it out. I think that of all the things that computers can do for mathematicians, this is the most valuable. You can ask "what about this" and the computer will do the grunt work. It's made a grad student's life much easier I'm sure :)

      --

      In Soviet America the banks rob you!
  20. Re:Godel/Turing/Cohen... by Hideyoshi · · Score: 3, Insightful

    No, they didn't "prove" any such thing - you've been reading too much Roger Penrose if you think so. There's absolutely no evidence that human minds have magical access to truths which formal systems don't; there once was a time when it was thought "obvious" that parallel lines could never meet, and it's still hard for many people to believe that there is no such thing as universal time.

  21. Theorem Proving by NitsujTPU · · Score: 2, Interesting

    Theorem proving is NP Complete.

    FOL Theorem provers jump through a number of hoops to make the whole bit a little more practical, but realistically speaking, having a computer that just runs through mathematical proofs in the manner that a human does is a long way off.

    An interesting thing about the article is that the first proof was done with an FOL prover... it was a long, non-intuitive proof, but an FOL prover has performed that proof.

    The second was done with code, a human had to write the program. There is no computer replacing the activity of a human in performing this action that I can see here. It was merely code to brute attack the problem from what I can see, but I didn't read the guys article (from what I can see, it hasn't reached publication yet anyway).

    1. Re:Theorem Proving by Anonymous Coward · · Score: 0
      Theorem proving is NP Complete.

      You think so? Prove it. Or show us a proof.

    2. Re:Theorem Proving by NitsujTPU · · Score: 2, Informative

      Here's a quick article on the topic. Should I have prefaced my statement with "if p != np?" I didn't think that we needed to stand to such scrutiny.

      I must, however, admit to a certain level of interest in the topic, so, if you want to have a more detailed conversation on the topic, I'd be glad to have a chit-chat sometime.

      Feel free to post your proof that P = NP, or a paper referencing a linear time FOL theorem prover or SAT solver ;-)

      http://en.wikipedia.org/wiki/Automated_theorem_pro ving

    3. Re:Theorem Proving by Anonymous Coward · · Score: 0
      Actually, based in the list of music choices on your web site - that's proof enough for me that you're correct. Seems we have large overlap in CD choices so I think you're right about the P=NP stuff.

      On the other hand, you're nuts to think that Stairway is a romantic song - I was always pissed that they cut off the second half and started drunkenly playing air-guitar to the part that they left off and pretended the floor was a mosh pit.

      Back on-topic - it almost seems to me that this is the way a lot of person-done proofs are accepted - people build some degree of respect/trust for the proover and read his stuff more generously. I imagine a computer-proof-generator program could eventually build the same level of trust; and other guys with their different computer-proof-checkers could check them.

    4. Re:Theorem Proving by NitsujTPU · · Score: 1

      I actually didn't make any statements regarding P's equivalence to NP. I just made a statement regarding FOL theorem proving. If we need to compare credentials, there are certainly better sources regarding my credentials than my outdated web site.

      All of that said, it's really not a question of whether or not the proofs are trustworthy, but whether an unaided computer can/will generate any interesting/useful proofs. I'm not going to try to distinct myself as an expert in automated theorem proving in a discussion with a troll, but my understanding is that, experimentally speaking, only a few interesting proofs have ever been produced by machines. To say that it is a bit premature to make the assertion that humans will be replaced in this task is an understatement.

    5. Re:Theorem Proving by Anonymous Coward · · Score: 0

      Actually, FOL Theorem proving is not even recursive, let alone in NP.

    6. Re:Theorem Proving by NitsujTPU · · Score: 1

      That is inaccurate.

      (Source, Wikipedia: "http://en.wikipedia.org/wiki/Automated_theorem_pr oving")

      Automated theorem proving (currently the most important subfield of automated reasoning) is the proving of mathematical theorems by a computer program. Depending on the underlying logic, the problem of deciding the validity of a theorem varies from trivial to impossible. For the frequent case of propositional logic, the problem is decidable but NP-complete, and hence only exponential time algorithms are believed to exist. For first-order logic it is recursively enumerable, i.e., given unbounded resources, any true theorem can eventually be proven, but invalid theorems cannot always be recognized. Despite these theoretical limits, practical theorem provers can solve many hard problems in these logics.

  22. Elegant proofs by erikkemperman · · Score: 2, Interesting

    I'm certainly not a very gifted mathematician, but I'd like to think my grasp on it is at least adequate to make this point: from the proofs I've seen and understood, it seems that while the shorter and more elegant proofs may not strictly be more "truthful" than complicated ugly ones, the important thing is they are so much easier to understand, verify, and explain to others. For instance, I remember being especially charmed by Cantor's diagonal argument and will not forget that particular method of reasoning for the rest of my life.

    But maybe there's a point where simple proofs just won't do it; if there were a 4 line proof for Fermat's last conjecture I'm sure someone would have found it before Andrew Wiles proved the thing in something like 80 pages.. In such cases, computer-aided reasoning is really the only way to go, I'd say. It's probably easier to verify a proofchecker than a proof.

    --
    Gosh, thanks. That must be why the other ships call me Meatfucker -- GCU Grey Area (Eccentric)
    1. Re:Elegant proofs by poopdeville · · Score: 1

      Wiles, Ribet, Serre, Shimura, Taniyama, and others wrote several thousand pages which together imply Fermat's last theorem.

      --
      After all, I am strangely colored.
  23. unverifiable by StrawberryFrog · · Score: 2, Interesting

    However, critics of computer-aided proofs say that the proofs are hard to verify due to the large number of steps and hence, may be inherently flawed.

    Nonsense. If people can't verify proofs, then what you need to do is to verify them by computer :)

    I'm not entirely joking here - so long as the verification program is written independantly of the thoerem-proving program, and it can reliably distinguish between valid and invalid logical inferences, what's the problem? It's simple automated testing methods really.

    --

    My Karma: ran over your Dogma
    StrawberryFrog

    1. Re:unverifiable by roju · · Score: 0, Troll

      Good idea. You write us a verifying program that can tell us if any given program will halt, and then we'll use it to test our theorem generator.

    2. Re:unverifiable by Sloppy · · Score: 1
      You write us a verifying program that can tell us if any given program will halt, and then we'll use it to test our theorem generator.
      I once started writing a program to do that, but it was a lot of work and I never finished it. So then I switched to a more powerful IDE, which would write the program for me. It's still running, but I think it'll be done any minute now.
      --
      As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
    3. Re:unverifiable by vanicat · · Score: 1

      Well, the Coq proof assistant is a program that make semi-automatic proof (semi automatic in the sense that some time it found the proof alone, and often you have to help him to find it). When you have finshid your proof, coq passe it to its proof verifier, and this proof verifier is a (relatively) small function that have been proved by hand (as for some problem linked to the Godel theorem, you cannot proof a theorem prover using it...)

      So its mainly the same idea: the proof assistant, and the proof verifier are disconnected (well, the proof assistant may use the proof verifier from time to time, but not the other way arround).

    4. Re:unverifiable by Anonymous Coward · · Score: 0

      What a non sequitur. People can't solve the halting problem either, but we currently rely on them to verify proofs. How is computer verification of proofs any worse?

  24. Hmpth by headkase · · Score: 1

    It's more like 90% pattern matching, 5% positive feedback effector systems and 5% adaptive selection of all engrams*.

    Source
    * A physical alteration thought to occur in living neural tissue in response to stimuli, posited as an explanation for memory.
    Um. Yeah. Or something like that.

    --
    Shh.
  25. Re:Godel/Turing/Cohen... by Anonymous Coward · · Score: 0
    Um, and indeed it's true that parallel lines never meet - unless you want to bend (pun intended, but it's true literally) the definition of parallel.

    Parallel lines - those who's (minimal) distance from each other is the same at any points - indeed do not have some places where they touch and others where they don't.

    If some silly mathemetician wants to publish a paper saying that he projected those lines on some curved space so now they touch - yet he still wants to call them parallel - that's a linguistics problem and not a math problem.

  26. clever - yes, short - no by S3D · · Score: 1


    Mathematical proofs should show short, clever ways of connecting otherwise disparate concepts that are only obvious in hindsight. Modern mathematics is very complex, important and useful theorems proven recently have huge and difficalt proofs, built from a lot of steps. Imortant results hardly have a short proofs.
    Take a look at the concepts used in the one of the most famous proofs of XX centery : the Feramt last theorem. It's proof followed from the Taniyama-Shimura theorem which establish non-obvious connection between quite different areas of mathematics. The proof is very long and complex, but of great importance for mathematics, and may have be realted to cryptography and even physics. Also such proofs are way outside of the power of near-future computers.

    1. Re:clever - yes, short - no by John+Allsup · · Score: 1

      I am writing up a PhD in pure mathematics and mathematical logic (group theory and PA). I know very well about how incomprehensible and long proofs can get. I've also had the pleasure of having to attack long papers in unrelated areas, and appreciate how ugly it can seem when you need to understand the result to help you with your research.

      Behind the proof of FLT lies a few very clever thoughts. The rest is either reuse of other concepts or mathematical language added so as to effectively communicate those thoughts: paper referees are partly there to help with this, and I recall that the FLT paper needed a few to facilitate its effective communication.

      You may of course choose not to see things the way I do, my points of view came about during my postgrad study. And I still think that the best proofs are the short ones: long proofs are the necessary alternative.

      --
      John_Chalisque
  27. Re:Godel/Turing/Cohen... by g1t>>v · · Score: 2, Funny

    That's what they said 50 years ago too ...

  28. Nothing too new? by xiaomonkey · · Score: 2, Informative

    Using computer programs to prove theorems in mathematics is as old as the field of artifical intelligence itself. In fact, some of the initial excitement around AI originated from the existence of such programs as Newell and Simon's Logical Theorist and it's sucessor the General Problem Solver .

    IIRC - back in the early days of AI (1960s), some people in the field thought that in relatively short order computers would be a major soucre of such mathematical proofs. It hasn't happened yet, but that doesn't mean that it won't eventually.

  29. Stupid post name by Anonymous Coward · · Score: 1, Insightful

    Who the hell came with this stupid name for the post?

    The article is about computer-aided proof, where the human makes the essential proof decisions while letting to the computer the tasks of properly formulating and performing very simple, yet laborious steps (which would otherwise draw the attention of the human from essential stuff).

    You **cannot** actually prove a really complex theorem in a fully automated way, because the reasoning is non-monotonic, which implies huge computational complexities. Machines are not yet good at being creative.

  30. Re:Godel/Turing/Cohen... by ivano · · Score: 0, Troll
    >> There's absolutely no evidence that human minds have magical access to truths which formal systems don't

    What has Penrose have to do with it? His little "quantum computers in our brain" has nothing to do with what I said. I gave you my sources: Cohen, Turning and Godel. That's it. Ask a logician if you don't believe me. All of these guys showed the limitations of formal systems (my bit about humans is irrelevant - and not very funny to begin with).

    Ciao

  31. Re:Consider the source by Anonymous Coward · · Score: 0

    That's true, they couldn't even spell Haken's name right. Also, it's unbelievable to write an article about mathematicians being replaced by computers without some reference to Doron Zeilberger.

  32. Re:Seems the computer is wrong by PakProtector · · Score: 1

    You should look at that map again. By simply eyeballing it and moving my mouse around Wyoming, I, a mere man, can easily tell it holds true.

    --

    Edward@Tomato - /home/Edward/ man woman
    man: no entry for woman in the manual.
    "Qua!?"

  33. Re:Seems the computer is wrong by tgv · · Score: 1

    No, it doesn't. Color Montana red, Idaho blue, Utah red, Colorado blue, Nebraska red, South Dakota blue, North Dakota yellow, and you only need a fourth color for Wyoming. Purple, perhaps...

    No, this theorem is pretty valid, and it is intuitively understandable. The only problem is that the only existing proof is rather long...

  34. Re:Seems the computer is wrong by MLopat · · Score: 1

    Okay, so we would simply need a political border where one area is enclosed in perfect square by other square areas. Simply put, the theorem is only true provided someone doesn't draw a map with that condition.

  35. Yesterday's news? by nextdoornerd · · Score: 0, Troll
    Ahemm.

    First, the story has been already discussed on technocrat.net day's ago (well, with 5 comments or so not really "discussed" as such :))

    Second, I have to run to have lunch now and then boys... I'm eager to wrestle over my master's subject with the whole /. crowde... Oh, the sanity :)

    Anyway, more to the point: it's not really AI, man. (At least nowadays.) Just some wonderfully pure math represented in (the most cases) painfully obfuscated, say, ML code >:\ (oh functionals, how I love thee... let me count the ways... uhm... zero? Ahemm.)

    1. Re:Yesterday's news? by gtall · · Score: 1

      Wow, an Artificially Intelligent human, keep on posting, it's all your program will allow for you to do.

  36. Re:Godel/Turing/Cohen... by Anonymous Coward · · Score: 0

    Your ignorance shows - of course they did prove it, and you would knew if you spent more time getting your facts than ranting at /. They proved that certain things *cannot* be proven in formal systems and that certain problems cannot be solved by computers/Turing machines.

  37. Re:Seems the computer is wrong by Anonymous Coward · · Score: 0

    Nope, you're just a fucking idiot.

    I'm not going to answer for you, but please think.

    Just because the state is surrounded by 6 states (which I'm guessing is your point) does not mean that 6 colours are neccesary.

    For instance without considering the other states, these 6 could be represented by just 3 colours, while still following the rules.

    Now think about what you have just said.

    Please think.

  38. Re:Godel/Turing/Cohen... by Anonymous Coward · · Score: 0

    You have no doubt because you're obviously clueless about principles of computers' operation.

  39. Re:Seems the computer is wrong by Anonymous Coward · · Score: 0

    Check it again. If you use four colors and analyze Wyoming, you assign one color to Wyoming and therefore have three colors to assign to boundary states. But the point is that the boundary states are not all adjacent to each other; therefore, you can use the color of a non-adjacent state. The only problem with applying this idea to political maps is that not all states are contiguous (and thus nonplanar), so the four-color theorem, while interesting, cannot be applied to real-world political maps.

  40. Incomputable math theorems by headkase · · Score: 1

    For a good introduction to incompleteness of mathematical systems people should really check out Godel, Escher, Bach: An eternal golden braid.
    This book basically describes Godel's incompleteness theorem in an entertaining way for a general audience.

    --
    Shh.
  41. Blowhard critics could use a logic course... by geekpuppySEA · · Score: 4, Insightful
    However, critics of computer-aided proofs say that the proofs are hard to verify due to the large number of steps and hence, may be inherently flawed.

    Because if there's one thing that humans are better at than computers, it's performing large numbers of repeated steps. Flawlessly.

    --
    Intelligent Design: because MATH is HARD.
    1. Re:Blowhard critics could use a logic course... by mcc · · Score: 4, Insightful

      One could argue that if a proof ever contains repetitive elements, then this is a bad thing and you want to be adding some sort of abstraction to the proof anyway.

      Anyway, the problem isn't the ability for the computer to perform flawlessly, the problem is in our ability to accurately specify to the computer what we want it to do. It's the whole "fast working idiot" thing, mechanical perfection isn't much good if we wind up just directing the computer to perfectly, flawlessly do the wrong thing very quickly. We have enough trouble convincing ourselves real-world software is going to do what we wanted it to after it compiles; and in that case we at least have the advantage we can run it and test it to see if it does what we expect. With software-generated proofs, not so much, since the program IS the test.

      I think computer aided logic can be useful if we just think of a proof-generating software program as a funny, mechanically verifiable sort of abstraction, but you find yourself making an argument that rests on assuming that a computer program you wrote does what you think it does then this is problematic.

    2. Re:Blowhard critics could use a logic course... by ceeam · · Score: 1

      Because if there's one thing that humans are better at than computers, it's performing large numbers of repeated steps. Flawlessly.

      Slashdot editors look like a hope for the humankind in this field.
    3. Re:Blowhard critics could use a logic course... by poopdeville · · Score: 1

      Sarcasm aside, computers are better at performing simple calculations quickly. Except when they aren't. Like when cosmic rays plow through my processor. Or when an implementation bug fucks up a computation. Mathematicians want certainty.

      --
      After all, I am strangely colored.
    4. Re:Blowhard critics could use a logic course... by Hangeron · · Score: 1

      So, a proof checking program would be like a debugger for mathematics?

    5. Re:Blowhard critics could use a logic course... by Dony · · Score: 1

      You raise a good point. Remember, however, that it is possible for computer programs to be flawed. I don't think this is a novel concept to anyone.

      It may, however, be possible to prove these theorems with the aid of a computer, thus eliminating the objection that these proofs are unverifyable.

      --
      Machiavelli, a graphic novel
    6. Re:Blowhard critics could use a logic course... by pyrros · · Score: 1


      >>However, critics of computer-aided proofs say that the proofs are hard to verify
      >>due to the large number of steps and hence, may be inherently flawed.

      >Because if there's one thing that humans are better at than computers,
      >it's performing large numbers of repeated steps. Flawlessly.

      You got the whole point backwards. It goes like this:

      1. Computer-made proofs are long and repetitive
      2. Humans suck at long and repetitive tasks
      3. Verifying a long and repetitive proof is a long and repetitive task

      Therefore: Humans suck at verifying computer-made proofs.

      This is a problem because if the proof-producing algorithm or it's implementation is flawed, the proof will probably be flawed too, and we won't really be able to tell, because WE SUCK AT IT. You could write another program to check the first one, but then you might need a third one to check the second one...

      All in all, what you need to do is prove, that your algorithm is correct (and be really careful with your implementation too), but now you are back to square one, only with a different thing to prove. Of course, in a lot of situations, the new problem IS simpler than the initial one, but it's not always the case.

    7. Re:Blowhard critics could use a logic course... by Mr.+McGibby · · Score: 1

      Mathematicians want certainty.

      And of course they get it, because no mathemetician has ever made a mistake.

      --
      Mad Software: Rantings on Developing So
    8. Re:Blowhard critics could use a logic course... by poopdeville · · Score: 1

      A mathematician might make a mistake, but it will get caught if the proof is in human readable form.

      --
      After all, I am strangely colored.
    9. Re:Blowhard critics could use a logic course... by danila · · Score: 1

      Look in the mirror. You are a nice example of human irrationality. A human, who illogically believes his belief that he is more logical than a computer is logical.

      You pretend your reasoning is sound, but in reality it's nothing more than primitive magical thinking. Write down a proof, give it to a mathematicial to read and he will magically verify it, while a computer will instead magically attract cosmic rays that will immediately flip all its bits. R-r-right.

      But of course, by virtue of being illogical and inconsistent you are immune to being proved wrong. No matter how well someone can show you your shortcomings, you just shrug it off and go on as if nothing have happened. Fortunately, people who are really rational usually have enough rationality to leave your kind alone.

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    10. Re:Blowhard critics could use a logic course... by Mr.+McGibby · · Score: 1

      but it will get caught

      Can you prove it will get caught?

      --
      Mad Software: Rantings on Developing So
    11. Re:Blowhard critics could use a logic course... by poopdeville · · Score: 1

      Jesus H. Christ, look at the context. We're talking about computer generated proofs that are too long to be verified by humans. The fact that a cosmic ray could cause a bit-flip and ruin a computation makes a purported proof not one until it is verified. Let alone the historical abundance of implementation bugs in software.

      I've already seen computer generated proofs. These are easily verifiable, if tedious to do so. They are proofs. A sequence of sentences, computer generated or not, is not a proof until verified.

      Now, before you go off and accuse people of magical thinking, you should learn a bit more literacy. Your characterization of my position is wildly incongruous with what I have written, in context. Kindly go fuck yourself next time you want to call someone irrational.

      --
      After all, I am strangely colored.
    12. Re:Blowhard critics could use a logic course... by danila · · Score: 1

      Grow up, kiddo.

      --
      Future Wiki -- If you don't think about the future, you cannot have one.
    13. Re:Blowhard critics could use a logic course... by Anonymous Coward · · Score: 0

      pwn3d.

    14. Re:Blowhard critics could use a logic course... by khallow · · Score: 1
      "What is actual function of a mathematical proof?"

      It is a certification that the statement is true. Your points are reasonably correct, but as you note they aren't a reliable proof checking technique with these large proofs. And frankly, human checking isn't that reliable even on short proofs.

      I see a reasonable need in the long term for a computer-based proof checker. The proof would be written (or more likely rewritten) in a computer-friendly format and then automatically checked for correctness by the proof-checker. The reason? Even with human checking, you can't be sure that the proof is correct.

      A well-vetted proof checker is a different story. The error is either in the proof-checker or in the proof. And we can make the proof-checker much more reliable than a human checker to reduce the chances of false positives.

  42. Re:Consider the source by Trogre · · Score: 4, Funny

    What does The Economist know? It's a right-wing rag.

    What does Slashdot know? It's a left-wing rag.

    --
    "Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
  43. Re:Consider the source by arodland · · Score: 0, Offtopic

    The Economist doesn't correspond to either of your pitiful, disgusting "wings", and that is good.

  44. here y'all go again, panicking... by Fry-kun · · Score: 3, Insightful

    To the opponents of computer-aided proof (with their hard-to-check argument), I would say this:
    It's easy to check a proof. It's hard to come up with a proof. Computers are great at checking proofs - all the program needs to do is verify whether the steps are logically correct or there's a discrepancy. Coming up with a proof, on the other hand, is a very hard task (being NP-complete, unless defined in a certain way) and thus usually requires a human (or sometimes, a lot of humans) to work on the problem.
    A computer would not be able to come up with new principles of mathematics in order to tackle a given problem, it would only try to use every trick that has been discovered to the point of creation of the program (of course that doesn't have to be the case, but my point is that human intervention would be required to "teach" the computer about the new concept so that it would try to use it for the proof)
    That is not to say that computers are useless in proofs. Obviously, they're often used as assistants in proving something-or-other, but there's also a direction in computer science where your computer would take a program that you wrote in a certain manner, and prove certain properties about it, e.g. that it is not possible to get out of array bounds in your C program...
    *yawn*
    time to sleep

    --
    Did you know that "FTW" ("for the win") is a direct translation of "Sieg Heil"?
    1. Re:here y'all go again, panicking... by jpc · · Score: 1


      The two issues that seem to have come up recently are:

      (a) the outputs of the computer proof generating programs are not in such a form as they can be simply verified as being a series of correct steps (either verified by another program or by a person), although some progress has been made towards this in a few cases (I imagine it makes it much harder to code)
      (b) some of the proofs have not been accepted for publication because no one will peer-review the code that produces the proof

      Both of these could be solved by doing a lot of work on how to write code for producing proofs, but I suspect that the types of problem people want to solve are very different, and lots of domain specific knownledge os needed. Also this type of software engineering is hard and would need a lot of funding.

      There has been talk about computerising parts of the existing body of proofs too, so that more experience was gained in how to formalise mathematics. I know everyone thinks maths is formal, but the notation is actually incredibly sloppy as far as computers are concerned, and will change many times during the course of a typical proof (adjacency is the main operator used for a start).

      Its a very interesting area.

    2. Re:here y'all go again, panicking... by Vo0k · · Score: 1

      Sooner or later someone will come up with code that can proof itself and the code that proofs theorems...

      uh.
      no.
      I think there's a flaw in that conception.

      --
      Anagram("United States of America") == "Dine out, taste a Mac, fries"
    3. Re:here y'all go again, panicking... by vanicat · · Score: 1

      Coming up with a proof, on the other hand, is a very hard task (being NP-complete, unless defined in a certain way) and thus usually requires a human (or sometimes, a lot of humans) to work on the problem.


      If generating a proof could be NP-complete, it would be a good news. But it is only "half computable", that is there is a program that will find you a proof if there exist one, but won't halt of there is none, and there is no program that will alway stop, telling you if there is, or not a proof. (I've already say it in one of my comment, put simply take the theorem "this turing machine will halt").

      Then even if you know that there is a proof, your theorem may use some non NP function, and so to proof your theorem you may need more than an expotancial time.

      NP-complete problem are not the most complex problem there is. A NP-complete problem is in NP, and some problem are not in NP.
  45. Re:Godel/Turing/Cohen... by Anonymous Coward · · Score: 0

    I think the point is that our brain is, in fact, a formal system -- just a very big one. All one needs to do is implement our brain as a computer, and we should be able to prove anything with that computer that we could with a human.

    dom

  46. Re:Seems the computer is wrong by Anonymous Coward · · Score: 0

    Get yourself a bit of paper and some coloured pens and play around for a bit.

    Any map (on a flat bit of paper) can be coloured that way.

    Now - it does NOT mean that given a pre-coloured map, you can't add areas that you can't colour. It just means that for those maps there was a DIFFERENT colouring which CAN be extended. You'll need to go back and recolour.

    But it does seem to be true, after you play around with it for a while. It's not possible (on a flat bit of paper) to make an area which touches four other areas each of which touch each other.
    Trying to do it, at some point you find that you have completely surrounded one of them, and you can then re-use that colour for your next area.

  47. Re:Consider the source by l-ascorbic · · Score: 2, Informative

    A right wing rag that backed Clinton and Kerry (albeit grudgingly), supports gay marriage, legalisation of drugs, gun control, abolishment of the death penalty..?

  48. Re:Consider the source by sien · · Score: 4, Insightful
    Umm. So does this mean right wingers can't do maths?

    Secondly, the claim that a magazine that opposes the death penalty and supports gay marriage is right-wing rag (which presumably you meant in US terms, is kinda amusing.

    The Economist, correctly stated, is a liberal magazine. It supports liberal economics and liberal social policy. Unfortunately the word 'liberal' in the US has been badly distorted.

  49. Re:Consider the source by Anonymous Coward · · Score: 0

    They've been around the block, but they're nobody special. Sorta like me.

    By virtue of your posting here on /., I have a hard time believing you've "been around the block". I have a hard enough time believing that you've been out of your parents' basement, much less the shower or even clean clothes.

  50. Re:Seems the computer is wrong by Anonymous Coward · · Score: 0

    Wyoming - Blue
    Montana - Red
    Idaho - Yellow
    Utah - Red
    Colorado - Yellow
    Nebraska - Red
    South Dakota - Yellow
    North Dakota - Blue

    I don't really see your point.

  51. Another Lomborg case? by orzetto · · Score: 2, Interesting

    The Economist is the same magazine that supported Bjørn Lomborg, thereby proving their utter incompetence in environmental science. They defended him in spite of clear and very detailed indications from the scientific environment that he was nuts.

    I suppose they will know economics when they talk about it, but they demonstrated an inappropriate habit of pontificating on things they don't have a clue about. I for one think they burned a lot of karma.

    --
    Victims of 9/11: <3000. Traffic in the US: >30,000/y
    1. Re:Another Lomborg case? by RedWizzard · · Score: 3, Interesting

      You linked to a "by invitation" editorial. That doesn't necessarily represent the normal views of the magazine. Have you got any further evidence they generally support Lomborg's views?

    2. Re:Another Lomborg case? by Dot.Com.CEO · · Score: 1
      The Economist is one of the finest magazines in circulation nowadays, exactly because sometimes they make mistakes. They are not afraid either to print controversial opinions or to say they are wrong - which, in this case they have done. They are truly independent - if you perceive them as liberal or conservative it is because you have not followed the magazine long enough.

      Also, their science and technology news and analysis is brilliant, it has consistently been a joy to read in the twelve years I have been reading the magazine, and their analysis while not always on the spot is certainly interesting and thought-provoking.

      --
      Mother is the best bet and don't let Satan draw you too fast.
    3. Re:Another Lomborg case? by Anonymous Coward · · Score: 0

      Look here: http://www.economist.com/displaystory.cfm?story_id =965520/
      This is pretty much the strongest editorial they put up in defense of Lomborg. You can also find more evidence by just going to www.economist.com and searching for Lomborg on the site.

      They stuck their foot pretty far up their mouth for this guy. If nothing else, it proves that for science news, you should go elsewhere. Besides, does anyone else think that it sometimes sounds like the science editor takes his articles from /.?

  52. Re:Consider the source by Anonymous Coward · · Score: 0
    IMHO the whole article was to get MBAs to feel smarter and/or more important than mathemeticians for a while.

  53. A proof needs to be intuitive by nigham · · Score: 4, Informative

    If you take a grad school AI course, they'll make you do proofs the way a computer does it... maybe using propositional logic. The idea is to break up the problem into a set of statements that looks quite ridiculous (e.g. NOT engine AND train AND NOT moving), and then taking pairs of these statements and mixing and matching. The result is that you determine your sequence steps by simple trial and error or by trying to combine the propositional symbols (AND, NOT etc) and the variables (train etc). Once you generate a proof, its just a list of such statements which evaluates to a FALSE or a TRUE value but if you want to understand the proof, its hopeless.

    I doubt the human proof system will go away completely - even if we can check nasty theorem proofs using computers, we still need humans to sit and explain what they mean.

    --
    I don't want to read /. I want to go home and re-think my life.
    1. Re:A proof needs to be intuitive by lisaparratt · · Score: 1

      This only applies if you're a mathematician - if you merely want to use mathematics, you only need to know that it works, not how it works or why it works.

    2. Re:A proof needs to be intuitive by Anonymous Coward · · Score: 0

      And I suppose you'll take someone's word that it works? :-/

      I mean, paint-by-numbers is OK, but some of us got really sick of it.

  54. Change roles? by archeopterix · · Score: 1
    Defenders of the same point out that there are non computer-aided proofs that are also rather large and unverifiable, like the Classification of Simple Finite Groups.
    That's why a different approach seems more appealing to me - humans write the proofs, computers check them. This approach is more promising, since verifying proofs is computable (well, except for some weirder logic systems), generating proofs is not (well, except for some weirder logic systems that are not very expressive).

    Such proof verifiers already exist today, but they are too stupid to be used to verify non-trivial theorems. They don't understand such paper-savers as "... other cases follow from this one" or "without loss of generality...". Of course, to allow such statements and still honestly check the proof, the verifier would have to generate some trivial parts of the proof itself - this is what human readers of mathematical papers do routinely. Are we thus back to square one (verification -> generation)? Well - proving the lemmas may be hard, but I think it's still much simpler than generating non trivial proofs.

  55. Subject by Legion303 · · Score: 1

    Until computers can routinely beat human chess players, pure mathematicians will still have jobs. Human intuition is generally better than computer brute-force when it comes to logical problems like these.

    1. Re:Subject by idlake · · Score: 1

      Are you trying to be subtly funny here? Computers can routinely beat human chess players, even the best of them.

    2. Re:Subject by Legion303 · · Score: 1

      I'm talking about Chessmaster, not a multimillion dollar cluster of CPUs.

  56. proofs?? by Androk · · Score: 1

    I, for one, need proof that these pr... errr. ummm, never mind.

  57. There's always room for creativity. by bombadier_beetle · · Score: 1

    Just because a tool is powerful, or its inner workings incomprehensible, does not mean that it cannot be used creatively or towards creative ends. In fact, one might assert the opposite.

    --

    If you mod me down, I shall become more powerful than you can possibly imagine.
  58. The one main advantage of computers... by boris_the_hacker · · Score: 1

    ... is that they allow you to make mistakes faster.

    I am currently hand proving some logic for my phd and it is a pain in the arse. I also have a tool that I have written to do the same thing.

    I still have to prove the logic is correct (by hand) and that the tool implements the proof search correctly (trickier) so I can then use the tool to solve bigger problems.

    Some of the proofs the program generates in under a minute takes myself days to do. (50+ pages of pdf generated from LaTeX).

    Through the development of the tool, I could validate from my hand written proofs whether it was generating correct proofs. Sometimes it would get things wrong and others it would do it better than myself.

    Computers are useful but only when we hardcode them with understanding that we have developed.

    --
    chris at darkrock dot co dot uk
    http colon slash slash www dot darkrock dot co dot uk
  59. Re:Consider the source by Anonymous Coward · · Score: 1, Insightful

    If by left-wing you mean "gun-toting, Europe-hating, and neoliberal", then I agree with you.

  60. I must be confused....the 4 color theorem.... by Anonymous Coward · · Score: 0

    states that 4 colors is enough to color any map.

    Even assuming that the one given example never occurs, where one segment might need to be the same color as another segment because they both belong to the same country, couldn't a segment have four or more borders with other segments?

    I don't know if perhaps it's never occurred with countries or with europe but even here in the states, don't we have states that share more than three borders with other states?

    Ok, I'm not big on geography, and I could be wrong. I could also be totally wrong about this as well, but it seems right off the bat that the theorem is flawed from out the gate.

    1. Re:I must be confused....the 4 color theorem.... by Anonymous Coward · · Score: 1, Funny

      oh come on.

      so if I have 30 countries all touching and one has borders with 7 of them, very simple to color it with only 4 colors, hell my 4 year old can figure that out.

      lay off the hemp and booze.

    2. Re:I must be confused....the 4 color theorem.... by PDAllen · · Score: 1

      You're thinking about chromatic number of a graph, where you colour edges of a graph.

      However, when you colour regions (or countries, or however you want to look at it) then maybe this country is touching a million other countries, but I will be able to find a way of colouring all those other countries using only red, green and blue, and I will still be able to colour the whole map with only four colours.

      (this has nothing really to do with real world geography maps, it just happens to be a nice way to visualise things)

    3. Re:I must be confused....the 4 color theorem.... by RackinFrackin · · Score: 1

      You are confusing chromatic number and chromatic index.

      The chromatic number of a graph is the minimum number of colours required to colour the vertices such that no two adjacent vertices have the same colour.

      The chromatic index or edge-chromatic number is the miniumum number of colours required to colour the edges of a graph such each vertex is incident with at most one edge of each colour.

    4. Re:I must be confused....the 4 color theorem.... by PDAllen · · Score: 1



      Yes.

  61. Re:Godel/Turing/Cohen... by ooze · · Score: 1

    Well, there will be devices that are not bound to formal systems (there are already, they are just not man made). Wether we still call them computers is a whole different question.

    --
    Just because I can imagine doing a hippopotamus, doesn't mean I'd like to do it.
  62. Mizar by ajb2718 · · Score: 2, Informative

    The most popular system for the computer-aided Formalized Mathematics is mizar. It even has it's own journal for proofs written with it.

  63. I am a mathematician and... by ratta · · Score: 2, Insightful

    I was surprised to find on ./ a title such as "The End of Mathematical Proofs by Humans?", but after reading the article i realized that the computer is only beeing used to speed-up calculations and the ideas are still born in the analogic human brain. I have always used computer programs in math to solve equation, to probe combinatorial game theory problems, etc... When you find a way to make the computer "invent" proofs, just let me know, i'll call it AI.

    --
    Wondering why i am doing so strange posts? I am trying to get a "+5,Flamebait" or "-1,Insightful" rating.
  64. Re:Seems the computer is wrong by UlfGabe · · Score: 1

    no, you are wrong.

    try again, if you look hard enough it will only take 4 colours

    --
    Check journal for info on Anti-TextBook, an idea by me.
  65. Re:Seems the computer is wrong by Anonymous Coward · · Score: 1, Informative

    The 4-color problem is only wrong if you require non-contiguous areas to be the same color, as might happen if you wanted to color a map of countries with Alaska being the same color as the rest of the USA.

    If you aren't talking about maps anymore, and are willing to discus arbitrary shapes, adding holes to the shape can mean it will need more colors.

    In either of these cases, you can create situtations where arbitrarily many colors are needed. However, the simple case of contiguous shapes on a continuous surface requires no more than 4 colors even though more are frequently used.

    dom

  66. I for one... by Anonymous Coward · · Score: 0

    welcome our new computer mathematician overlords!

  67. Science by AI is flawed too by Anonymous Coward · · Score: 0
    Read "Goedel, Escher, Bach". A great book on this topic. It goes im more detail on topics like this:
    This very statement CANNOT be proven by AI.
    You will see the EVERY formal system has its flaw. try to proof the following statement:
    This very statement CANNOT be proven by a slashdot reader.
    AI will be able to prove it true. Even my mom can prove it true, but you and I can't.
    1. Re:Science by AI is flawed too by Professor+S.+Brown · · Score: 2, Funny

      Was that just an intentionally terrible example, or did you not actaully understand a good portion of the book?

      --
      Shitram Brown, PhD
      Professor of Mathematics
  68. TI-83? HP-48! by Anonymous Coward · · Score: 0

    Please don't mod this flamebait; this is geekbait.

  69. "peer" review by lucason · · Score: 5, Funny

    How can the review of proof generated by computer by a human be considered "peer" review?

    Why not have it verrified by other computers?

    1. Re:"peer" review by Suhas · · Score: 1

      Funny??? Oh come on give the guy some Karma. Make it Insightful.

    2. Re:"peer" review by igny · · Score: 1

      Why not have it verrified by other computers?

      What if you have two "unverifiable" computer proofs proving the opposite? Which proof to publish then?

      --
      In theory there is no difference between theory and practice. In practice there is. - Yogi Berra
  70. Did I broke something? by yess · · Score: 1

    Whoaa! On Monday I was given an assignment to code a program that will prove a simple theorem from first order predicate calculus. I coded in in python on Tuesday in about an hour. The code isn't fast, but nevertheless works. On Wednesday The Economist writes about all the maths falling apart because of me?

  71. BTW, as a geek I want to know by ceeam · · Score: 3, Interesting

    What do they use for this field? Prolog still or something new(er) has been invented? Or they do what businesses do and use whatever comes handy or whatever is the current fad?

    1. Re:BTW, as a geek I want to know by Maljin+Jolt · · Score: 4, Informative
      A functional Haskell language is the tool of the day. However, there is nothing in Haskell that could not be done in Prolog with proper problem domain language defined by grammar. H. is just fancy looking, out of the box. Unlike Lisp.
      reverse :: [a] -> [a]
      reverse = foldl (flip (:)) []
      applied to a finite list of any type, returns a list of the same elements in reverse order.
      --
      There you are, staring at me again.
    2. Re:BTW, as a geek I want to know by call+-151 · · Score: 2, Informative

      Actually, the proofs under discussion are not generated by a computer nor do they use "computer reasoning systems" like Prolog. These are computer-aided proofs, where the outline of the general argument is constucted by a (human) mathematician, but some of the details are reduced to computations, which are done by computer. I don't know in what language these particular computations were done, but I know that the computations for the computer-aided proof of the double-bubble conjecture was done in C++, and the source code is available if you want to have a look. I am familiar with other such computer-aided proofs that use a diverse set of languages, including C, assembly, Perl, GAP, Magnus, Mathematica, AXIOM, and many others. Mathematicians, like other researchers, tend to have diverse opinions about what suitable computational tools are and also tend to use the tools with which they are most familiar, even if that tool is not really optimal for that computational task.

      --
      It's psychosomatic. You need a lobotomy. I'll get a saw.
    3. Re:BTW, as a geek I want to know by Anonymous Coward · · Score: 1, Informative

      Fancy shmancy.

      (defun rev (a &optional res)
      (if (null a)
      res ;; haskell line 1
      (rev (rest a) (cons (first a) res))) ;; haskell line 2

      This reminds me of when someone argued that the Haskell example of Quicksort couldn't be done as elegantly in Lisp. Turns out it's trivial to write it *exactly* the same way in Lisp as in Haskell, and it's shorter to boot.

    4. Re:BTW, as a geek I want to know by sv0f · · Score: 1
      (defun rev2 (a)
      (reduce #'cons a :from-end t :initial-value '()))
      Or the even simpler:
      (defun rev3 (a)
      (reverse a))
      Or the potentially more efficient:
      (defun rev3 (a)
      (nreverse a))
      ;-)
  72. Re:Godel/Turing/Cohen... by sperxios10 · · Score: 1, Informative

    I've been reading so much of Penrose and here is my 2-cent about his views...

    Turing's theorem, in brief (neglecting sound-ness of algorithms), dictates that there is no single algorithm that can "prove" the non-termination of all algorithms.

    The above (combined with Godel's theorem) means that, no single program can prove all theorems , which i think is correct.

    So, you have to use different algorithms for certain problems. But in order to "devise" those new algorithms, you need to solve the (Turing's) problem of termination on those algorithms (indeed , programers-mathematicians do manage to solve it!)

    So, in essence Penrose prooved that, humans are SOMEHOW more capable than computers, since they can (in principal) solve the termination problem of all algorithms.

    Now, Penrose also believes that this capability may originate from the access of humans mind in pure truth (or what ever) but those are his beliefs, not his mathamatical proofs. You are not obliged to follow them.

  73. relax by mat.h · · Score: 2, Informative
    You still have to tell the computer what to prove. Much of what mathematicians do is finding the right concepts and formulating propositions. Then you can try to prove these propositions.

    A fairly basic example: several centuries passed between Newton and Leibniz introducing derivatives and Cauchy and Weierstraß arriving at the formulation that's taught in high schools nowadays (at least where I live): epsilon-delta definition of the limit and going from there. Today, this stuff and the accompanying proofs look pretty simple (and they are), but without the right formalism/mental model, playing with infinitesimal quantities is somewhat of a black art. It took a long time to get there, and computers wouldn't have helped much.

    1. Re:relax by Kryft · · Score: 1

      You still have to tell the computer what to prove.

      Indeed. Generating proofs is a bit like generating code. I can picture a computer generating proofs or code, but at least in the foreseeable future, I can't see a computer thinking of interesting conjectures (things to prove) or program designs (things to code).

      Because most people encounter math as a tidy collection of Big Theorems and their accompanying proofs --- after all, even those who take math at university aren't likely to see anything remotely new unless they're math graduate students --- and because math usually only makes the news papers when someone has solved a really hard problem (like proving Fermat's last theorem), it's easy to get the impression that what mathematicians do is basically trying to come up with proofs for More Or Less Big Theorems. I'm only a budding math major myself, but I get the impression that the problem most mathematicians (well, the researchers anyway) face is rather that of finding interesting things to prove. Software can definitely help, but only as the tool of a mathematician.

  74. Re:Godel/Turing/Cohen... by poopdeville · · Score: 2, Insightful

    This is dumb. Godel showed that there are non-standard models of arithmetic. This means that there are distinct, non-isomorphic sets of objects which satisfy the axioms of Peano arithmetic. There's no talk of formal systems in his proof.

    Turing applied Godel's work to Turing machines and showed that there are non-recursive functions. No talk of formal systems here.

    I have no idea why you're mentioning Cohen, since his most famous work had to do with showing that there are models in which the Continuum hypothesis fails and models in which the Axiom of Choice fails. Not related to formal systems at all. Just Zermelo-Fraenkel set theory.

    All of this is tangential. Assuming a generous reading of "formal system" as "formal logic, your alleged "limitations" to formal systems come down to a simple corollary of Godel's completeness theorem: Given a fixed set of sentences S, there is a proof of A from S iff A is true in every model of S.

    --
    After all, I am strangely colored.
  75. much of math is horrendously inelegant by idlake · · Score: 1

    The best math is always elegant.

    Even if you consider constructs like the reals, they are actually quite inelegant. The same can be said for a lot of other mathematical constructs and proofs.

    The problem with modern computer aided proofs is they allow the proof to become unwieldy and overly verbose, compared to what it would have to be if just a human produced it.

    The problem with a lot of human proofs is that they are wrong and that they are wrong in such subtle ways that human readers don't notice.

  76. Re:Godel/Turing/Cohen... by Sloppy · · Score: 1

    Yeah, but future computers will be able to do it, because they'll be fusion-powered.

    --
    As copyright owner of this comment, I authorize everyone to defeat any technological measure which limits access to it.
  77. Proof theory and metamathematics by Anonymous Coward · · Score: 0

    However, critics of computer-aided proofs say that the proofs are hard to verify due to the large number of steps and hence, may be inherently flawed.

    However, critics of critics of computer-aided proofs say that critics of computer-aided proofs should get around to solving Hilbert's 24th problem.

    Hilbert prepared 24 open problems to present at the second International Congress of Mathematicians in 1900. For reasons that are not entirely clear, he only presented the first 23.

    The 24th problem is a metamathematical problem in the field of proof theory. In brief, it asks for criteria of simplicity, i.e. guidelines by which you can prove that a particular proof is of maximal simplicity.

    Until Hilbert's 24th problem is solved, our only hope for proving that particular proofs are maximally simple is through computational means.

  78. Halt! by StrawberryFrog · · Score: 1

    Ha ha. Is finding a fault in a theorem the same as, or even in the same category as, The halting problem?

    --

    My Karma: ran over your Dogma
    StrawberryFrog

    1. Re:Halt! by vanicat · · Score: 1

      Well, to find if it exist, or not, a proof to some logical formula is in the same category as the halting problem: You can (if the logic you use is powerfull engought), for each Turing machine, wrote a formula that is provable if and only if the turing machine will halt. But to verify a proof is much easier: is more or less as easy as to verify that a description of a (finite) run of a turing machine is actually the run of the say turing machine, and not something else.

    2. Re:Halt! by Vo0k · · Score: 1

      Yes, but it's a narrow subcategory - it's a single theorem, single problem. Like an automated testing device that is technically capable (or can't, because it's broken) test a number of devices, including itself. You're never sure if the result is valid if you use it for testing itself. But if you can use other, proven (even if way less efficient and working in much narrower area) techniques to test that device, proving it works okay, you can test anything using it.

      (seems people from Microsoft, the "Get the facts" campaign, don't quite get that idea...)

      --
      Anagram("United States of America") == "Dine out, taste a Mac, fries"
  79. Re:Godel/Turing/Cohen... by j.blechert · · Score: 1

    > Why can't human brain functions be copied and improved[...] perhaps a lot of our intelect is not located in the brain but elsewhere, would be nothing new to discover some world-shattering news in this area of research...

  80. Re:Consider the source by earthbound+kid · · Score: 1

    Ah yes, because whether computer based proofs is a good thing or not is a right v. left issue. Good call! I was almost afraid to think for myself for a second there, but now that I understand that only right-wing people trust the Economist, I can spout a party line much more efficiently.

    For crying fuck's sake man, I consider myself left of center, but it's this kind of "us versus them" mentality that makes me sick of the whole political system. You know, not every issue can be decided by checking party affiliation! Sometimes you have to puzzle it out yourself. If that's too much for me to ask, you can have your Michael Moores and Rush Limbaughs to yourself and count me the hell out!

  81. Motivation by beacher · · Score: 1, Funny

    Speaking of toys - I found this on Thinkgeek.com and it's a perfect for your favorite mathematician. " If A Pretty Poster And A Cute Saying Are All It Takes To Motivate You, You Probably Have A Very Easy Job. The Kind Robots Will Be Doing Soon.". Seems very apropos....

  82. Not just (or mainly) others ... by guybarr · · Score: 1


    A mathematical proof is nothing but a manner of convincing someone (other mathematicians) that what you assert is indeed correct

    More correctly, I would say:

    A mathematical proof is the method of convincing mathematicians (the first one being yourself) that what you assert is indeed correct.

    This, of course, only strenghthens your concluding sentence...

    --
    Working for necessity's mother.
  83. Re:R. Daneel? Is that you? by maxwell+demon · · Score: 1

    But the question is: Will they also post on slashdot?

    --
    The Tao of math: The numbers you can count are not the real numbers.
  84. Re:Seems the computer is wrong by Anonymous Coward · · Score: 0

    Okay, color Wyoming one color. You have 3 colors left to work with. Starting with Montana and working your way clockwise, color them so: 1-2-3-2-1-2-3. No adjacent states will be the same color. That leaves Wyoming itself to be colored with color 4.

  85. Godel? by igb · · Score: 2, Informative
    Automated theorem proving was the purpose of
    Russel and Whitehead's work in Principia Mathematica, amplified by the Hilbert Programme.
    Godel exploded that little lot by showing how
    any formal system powerful enough to represent
    anything worthwhile was powerful enough to
    contain contradictions.


    Even simple `proof' like n-satisfiability or
    showing that a string is a member of a language
    defined by a context-free grammar is NP complete.


    ian

    1. Re:Godel? by Anonymous Coward · · Score: 0

      What about the shitload of stuff that can be proven by computers? Sure, you can't prove everything about number theory, for instance, using propositional logic, but most true statements can be proven.

    2. Re:Godel? by genneth · · Score: 1

      That is wildly inaccurate. Godel showed that all formalisations of number theory are essentially incomplete, by having real truths of number theory not being a theorem. This is not disastrous. He also showed that any formal number system that could show it's consistent (contains no internal inconsistencies), would in fact, be wrong and is inconsistent. This is not disastrous either. If it were to "contain contradictions" as you put it, it WOULD be absolutely disastrous, since then it would be useless. Formal logic != human thinking, a contradiction is a cancer that causes all statements to become theorems.

    3. Re:Godel? by cognition · · Score: 1

      The other main problem is that the theorem of a set of sentences strenghtening Peano arithmetic (minus induction) is not recursive, this makes it impossible for a machine to recursively (i.e. within a boundary) decide whether a particular sentence is true [Church's Theorem].

      This means that if a computer wanted to decide whether something was true or not in a particular formal system, then the computation to do so could last forever.

    4. Re:Godel? by cognition · · Score: 1

      Actually I'm wrong there, I was thinking of "primitive" recursive, I meant to say that if something is not recursive then it is (intuitively) not computable at all.

  86. Embrace both methods by karvind · · Score: 2, Interesting
    My take is that computers are a liberation from mindless computation and a tool for exploration. Only the most severe of Luddites wouldn't use a calculator, a computer is just an extension of that. For example, factorising polynomials, solving equations symbolically, and so forth. These are the sort of things that computers can save us an enormous amount of grunt work doing. Why not use them?

    For exploration, they are also useful. New series for p have been conjectured (and proved by hand) based on computer programs which search for certain sorts of integer relations. This has led to the ability to find the nth hexadecimal digit of p without finding the previous n-1 digits, something that could have been exceedingly difficult without this computer program.

    With regard to things like the proof of the 4 colour theorem using computers, there is a more interesting debate here. I'm going to make an analogy with a similar debate in neuroscience which is quite interesting. David Marr, who was a researcher into visual systems in the brain, made a distinction between Type 1 and Type 2 theories. A Type 1 theory is, broadly, one in which there are nice formulas like you get in physics or maths. A Type 2 theory is essentially computational. For example, many models of the way the brain work use PDP (parallel distributed processing, a sort of computer model of neurons in the brain). Marr's point was that in general we should prefer Type 1 theories, because they give us a general and intuitive understanding of how the thing being studied works. For example, there are certain cells in the visual system which detect edges in the visual field. So, if you have a theory of vision which involves certain cells finding the edges in the visual field then that gives you a better understanding than some sort of computation model which performs the function of the visual system but which you don't really understand. However, he also pointed out that since animals evolved and were not designed, there may not always be a Type 1 theory explaining why, in an abstract general way, the brain (or any other bit of the body) worked, it just does.

    Returning to maths, I think the analogy is that a Type 1 theory is one which can be completely understood by a single individual by working through it line by line, whereas a Type 2 theory might involve a computer proof like in the 4 colour theorem. In general, we prefer to get proofs which don't use computers, because they might give us an intuitive insight into why the theorem is true, or it might lead to an interesting new branch of maths (like the Taniyama-Shimura conjecture that Wiles proved). However, there might be some theorems which just do not have proofs which a single person could read and fully understand. The 4 colour theorem might be just such an example. It would be foolish to discount any such theorems a priori, and so I would advocate a cautious use of computers in mathematical proof. The danger in overusing computers is that if they become too widely used, people will search for computer proofs without finding the insightful way of solving the problem which doesn't use a computer. The danger in not using them enough is that huge amounts of effort could be wasted trying to find neat analytical solutions to problems which are not really amenable to traditional methods (not using a computer) of attack.

  87. Can it prove the Riemann Hypothesis? by alphadingo · · Score: 2, Funny

    I'd pay $500,000 for a program that can prove the Riemann Hypothesis.

    1. Re:Can it prove the Riemann Hypothesis? by sgant · · Score: 1

      Oh yeah? I'll pay a million dollars for a program that does that! then I'll win the Millennium prize of a million dollars and I'll earn like...a Million dollars...or like 50,000 or something after I pay you off...or around there...

      I'm not good a math...

      --

      "Leo Fender was in a 'state of grace' when he designed the Stratocaster." -- Paul Reed Smith
    2. Re:Can it prove the Riemann Hypothesis? by coopex · · Score: 1

      I have a proof but the comment box is too small to contain it. If you could send it to: Olusegun Obasanjo 7, Mambilla Street, Off Aso Drive Maitama District, Abuja Nigeria I would be able to send it next day. Thank you.

      --
      The road to hell is paved with good intentions.
  88. Godel's Theorem prevents this scenario by Anonymous Coward · · Score: 0

    Godel's Theorem prevents this scenario. Computers might be able to prove some theorems but not all of them.

    A pure computer with no external inputs or outputs cannot deduct something that is not inherent in the logic it possess. Should there be external inputs to break the closed logic system, the computer would not be able to prove everything, only a small subset (it would be impossible to find the answer the everything, live the universe and everything else unless the computer has at least as many states as the universe). It is the same with humans - we cannot possible prove or disprove the existance of A/The Creator in a finite universe.

    1. Re:Godel's Theorem prevents this scenario by PDAllen · · Score: 2, Insightful

      A computer can prove any theorem, if you give it long enough.

      Reason: a theorem is a statement which has a proof. A proof is a finite sequence of logical statements. You can order all sequences of logical statements by lexicographic order within the sum of the number of variables used and the number of statements; then simply have a computer run through all sequences of logical statements in that order, checking each one to see whether the statements in the sequence are either axioms or follow by the rules of logic from the axioms, and checking whether the final statement is the statement you want to have proved. The computer will eventually reach a proof of whatever theorem you asked it to prove. Note that if you asked it to prove a statement which is not a theorem, it will never stop. Goedel's theorem tells us that there are some statements where not only will the computer fail to prove the statement true, it will also never prove the statement false.

      The problem with trying to do this in practice is that for any interesting problem the shortest proof might not fit in a telephone directory - and the computer would be trying to find it by checking through all sequences of that size. It would take far too long.

      The theoretical problem you refer to is whether one can write a program which will correctly classify all statements as true or false - this is not possible; some statements are neither. If you allow it to classify as 'neither' as well, it is still not possible - the sketch above will never classify any statement as 'neither' because with such statements it never halts, for example. Turing proved that no program can correctly classify all statements.

  89. SPOILER for ROTS movie in /. article? by Provocateur · · Score: 1

    causing mathematicians to 're-examine the foundations of their discipline

    ...and Obi-wan was never heard from again. Some stories claim that he is living in a cave on a desert planet in a distant galaxy. Rejecting the use of technology, the stories claim that he is now using two sticks to build a fire which will keep him warm at night...

    --
    WARNING: Smartphones have side effects--most of them undocumented.
  90. Re:Test mod-bots by Omniscientist · · Score: 0, Offtopic

    I'm tempted to mod up parent AC as funny because it is hilarious that he/she was actually modded as troll, but...well that would destroy the whole point.

  91. Proof by computer is no mathematics by Anonymous Coward · · Score: 0

    As Grothendieck is said to have stated:
    "Do not try to proof things that do not look
    trivial to you."

    There are seldom things like Riemann hypothesis,
    that you can formulate but not proof or falsify.
    And if you could get a "is proveable" or "is false" (and more a computer would not be able to) almost nothing is won.

    Only having true or false sentences does not explain anything. You understand nothing more, and there is nothing you can do more with it.

  92. Penrose by Anonymous Coward · · Score: 1, Informative

    A dekko at Penrose's "Emperor's New Mind" and "Shadows of Mind" is worthwhile. He presents what are (IMHO) fairly convicing arguments that what mathematicians do (actually, what humans do, but he uses mathematicians as the basis for his argument) is not computable (in the Turing sense).

    1. Re:Penrose by Anonymous Coward · · Score: 0

      Actually Penrose is full of shit. He uses handwavy arguments to describe 'human thought' in a way that *looks* different from the handwavy arguments he uses to describe 'computation in the Turing sense.' But he comes nowhere near a proof.

  93. Been going on a long time by biglig2 · · Score: 1

    Don't they say Gauss was the last man to be able to hold pretty much all of Mathematics in his head? After that, it got too much.

    --
    ~~~~~ BigLig2? You mean there's another one of me?
  94. I agree with Erdos by yderf · · Score: 2, Interesting

    Proofs where no one understands the proof are of little use. Yes they allow you to work with the statement that was proven, but you don't garner anything from the proof itself.

    Many nice and elegant proofs are just that because they are not only aesthetically pleasing, they also give their readers insight into other problems.

    As Erdos used to say, they come straight from the SF's book. (if you don't know what that means, go read about him)

  95. Inaccurate by acaspis · · Score: 1

    the use of computers to generate proofs is causing mathematicians to 're-examine the foundations of their discipline.'

    They should be concerned about the use of computers to generate new formulas and conjectures, which is where the creativity is.

    critics of computer-aided proofs say that the proofs are hard to verify due to the large number of steps and hence, may be inherently flawed.

    Bullshit. Computer-aided proofs are also computer-verified. And only computers generate useful computer-verified proofs, because most humans are too proud to submit themselves to such unforgiving examination. (And because it takes an awful lot of boring work, too).

    What you loose is the elegance of a short proof. But a nice-looking proof can be incorrect too (e.g. a geometric figure which doesn't cover all cases.)

    The article sounds a bit like Microsoft PR saying they are investing in state-of-the art techniques to produce bug-free software. Which is good. But be sure to read the full credits.

  96. Well, a lot of us are happy of this... by DownloadTHIS · · Score: 2, Funny

    The end of mathematical proofs by humans? I think I speak for the entire high school populus by saying "Thank God!"

  97. Flawed reasoning by kassemi · · Score: 1

    Although I'm no expert, I was drilled by my father (phd thermodynamics) on the importance of the human mind in proofs. He solved a problem in the late seventies (albeit that was some time ago), that computers were having issues with until about ten years ago. A program is a program. A procedural method for determining whether or not. It loops continuously searching for truths until it finds one and continues on to the next search. A program merely demonstrates the programmer's knowledge of the problem. No program will take a perfect approach to solving a problem unless the programmer knows what that approach is. Take for instance a very simple root calculation. We have a function, f(x) = x^2 - 4. Have a computer determine the two roots of that one, and you end up with the same answer that you find on your own: x=+/- 2. A program can take a look at the format of the function and take a guess at what the solution will be, or it can just follow along all the values until it finds an f(x) = 0... When we look at that, we realize the nature of the curve without needing to look at the format of the formula. It appears in our minds, and we can determine what the roots should be using a non-procedural method. You may argue that we do use a procedural method to calculate the solution... Even if this solution was forced into my subconcious through years of school, we have to take a look at the problem and just imagine how the hell a computer is going to figure out the procedure for solving that... Frankly, it's when we've been sitting in front of some data for a long while that we find the solutions to all problems. I believe strongly that this is because our mind starts to wonder, contemplating things that are seemingly irrelevant, pushing us toward processing a different method that will work. Our world's greatest ideas were always inspired by something other than the knowledge required to formulate that idea. Hmm... I hope that little rant is suitably confusing :). Sincerely, James.

    --
    What the hell's a "gewie?"
  98. There is no such thing! by N3wsByt3 · · Score: 0

    It has been mathematically proven that there is no such thing as a mathematical proof!!

    --
    --- "To pee or not to pee, that is the question." ---
  99. What is the truth? by mario_grgic · · Score: 1

    This brings a very interesting point. It raises the question of what is the truth. And the truth is only something humans can verify, at least right now it is. Scientists and mathematicians particularly are called to be sceptics and never accept anything as true without first understanding it and re-validating it to themselves, which involves going through the motions and validating the rigidity of each implication in a mathematical proof. If that can't possibly be done by a human, the truth of the proof can't be accepted by the human either, which means that it isn't necessarily true to a human.

    --
    As the island of our knowledge grows, so does the shore of our ignorance.
  100. Wake up! by oriol · · Score: 1

    Learning how to do mathematical proofs is of great interest for the development of children!
    It allows them to reason about something and have an idea about what is right and what is wrong and that there are things that are right and others that are wrong.

    From another point of view, are computer scientists still really have something to prove to the rest of the scientific community so that they have to cheer up because they have the feeling that they beat mathematicians?

    My real point is that mathematics and CS inherently have two different ways of stating problems:
    - Mathematics: complex problems -> complex proofs that should not be complicated (e.g. recursive proofs).
    - CS: simple problems -> simple, yet repetitive/complicated, proofs (soundness proofs).

    It is rather but an accident that CS is able to prove anything in the math field.
    Btw, what is the point to prove something that nobody can understand (cf the answer is 42)?

    So my advice is wake up guies! We, as cs people, are not meant to be the best/most powerful scientists! As each scientist we have our own domain, and it happens that we are the ones who built computers/software which are used by others, in the same sense that electrical engineering 'made' electricity. We are no more and no less than that.

  101. 4 color theorem by geordieboy · · Score: 1

    It's Wolfgang Haken, not Harken

    --
    The world is everything that is the case
  102. Goedel's Incompleteness Theorem and Independence by ai0524 · · Score: 1

    Mathematics is recursively axiomatizable by the axioms of ZFC. Goedel's Incompleteness Theorem says that the theory (the set of logical sentences provable from ZFC, i.e. mathematical theorems) must be incomplete. So there are some sentences that are not provable within ZFC. There can be no algorithm for deciding which sentences are unprovable in ZFC. Since most mathematicians don't care about independent sentences it is true that most theorems could be proven by computers - although at this time automated theorem provers are not very efficient. However for Logicians, and in particular Set Theorists, who do study such independent propositions (like the Continuum Hypothesis) do care to know what these independent sentences are and cannot be replaced by computers in studying them.

    --
    Share bicycle touring info worldwide: http://wheretocycle.com
  103. 1=2 by Anonymous Coward · · Score: 0

    Something a friend of mine showed me a while back.
    1*0=0, therefore 1=0/0
    2*0=0, therefore 2=0/0
    by transitive property of equality, 1=0/0=2, or 1=2.

    I'd pay $500,000 for a computer that agrees with me.

  104. I love proofs by n-baxley · · Score: 2, Interesting

    I loved doing proofs in my High School math classes. I even had my own book of axioms, thereby cementing my destiny to be reading /. someday. I didn't become a mathematician, but the merger of logic and creativity was so appealing. I wish I had been able to take it further, but unfortunatly calculus came along and whipped my but, so instead of an engineer, I became a programmer. Go figure.

  105. not for all cases by jonathanduty · · Score: 1

    " use of computers to generate proofs"

    Won't work for all cases. Can anyone say the halting problem? (forgive me if I'm wrong, its been a while since computation theory).

  106. but (a) should not be true. by raboofje · · Score: 1

    Systems that have problem (a) are indeed pretty useless from a math point of view.

    However, most prooftools, like CoQ, HOL and Mizar (correct me if i'm wrong here) actually do produce an easily-checkable version of the proof. That makes (b) irrelevant: if a specific resulting proof is checked by the checker, it's OK, regardless of how it was generated.

  107. The proof is sometimes the easy part by T+Rat · · Score: 2, Insightful

    Perhaps the most difficult part in my own work as a mathematician is understanding an area well enough to create meaningful, interesting conjectures. In many cases, the proof falls out immediately. This obviously isn't universally true (e.g. Fermat's Last Theorem), but the mathematicians that I have the most respect for are the ones who are able to see the connections between seemingly unrelated areas and ask the right questions to pull it all together.

    As other have said, computing may be able to verify an existing proof, but I think the real creativity and beauty in mathematics is often found in the initial formation of the conjecture.

  108. A few good proofs by bonvoyage · · Score: 1

    Your want proof!? You can't handle the proof!!

  109. Computers need proofs by humans by pkturner · · Score: 1

    Humans have been creating more and more proofs for the benefit of computers. They're just not recognized as such because these efforts are independent of mainstream mathematics.

    It's called computer programming. The Curry-Howard correspondence demonstrates that every program in a statically typed language represents a proof, with the same kind of formality as the mathematical proofs mentioned in the article.

  110. computerising parts of the existing body of proofs by raboofje · · Score: 1

    About computerising parts of the existing body of proofs: there's a *lot* of lemma's formalized in the Mizar Math Library, all automatically checked. Browse it at: http://www.mizar.org/JFM/

  111. Outsourcing proofs to Indian schools by Anonymous Coward · · Score: 0

    We don't care how you do it, as long as it gets done -- more cheaply than we can do it.

  112. Issac Azimov story by Conspiracy_Of_Doves · · Score: 4, Interesting

    I recall a story I once read by Issac Azimov about a future culture where all knowledge of mathematics has been lost to humans, who have to rely on computers and calulators to do even the simplest math problems (older computers make the new computers and humans are left completly out of the process).

    A janitor at a science lab rediscovers the 'ancient knowledge' on his own. The military quickly gets ahold of it and immediatly puts it to use in weapons research, whereapon the janitor promptly takes his own life in shame.

    Anyone think there might be a future where humans rely on computers so much that they don't bother learning math at all any more?

    1. Re:Issac Azimov story by mikael · · Score: 1

      Anyone think there might be a future where humans rely on computers so much that they don't bother learning math at all any more?

      I thought we were already there. How many people truly understand how their digital satellite/cable box works? All they know is that you have to place a dish on a solid foundation and point it at a clearly visible point in the sky, and keep it connected to a power supply and TV. The need to understand how polarised Gigahertz signals are transmitted and received, how satellites are launched into and remain in geostationary orbit, how systems are duplicated to prevent failure, and how digital compression and encryption algorithms operate isn't necessary. All they need to know is how to switch the machine on/off, adjust the volume and change channel.

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
    2. Re:Issac Azimov story by Conspiracy_Of_Doves · · Score: 1

      I mean a future where people can't even do 2*3 without a calculator.

      Although now that I think about it, chances are that we will eventually have computers implanted in our brains that do all kinds of things, one of which will be to instantly give us the answer to any math problem that enters our heads.

      One problem that arises from that is that learning math is the beginning of learning how to think logically.

    3. Re:Issac Azimov story by coopex · · Score: 1
      --
      The road to hell is paved with good intentions.
    4. Re:Issac Azimov story by mikael · · Score: 1

      I mean a future where people can't even do 2*3 without a calculator.


      I don't think so - even in socially deprived areas where the majority of school-leavers don't go to college, and the black market is the only form of trade, people still instinctively know a good deal from a bad deal.

      Having augmented intelligence will probably become a reality though - combine a miniature video camera mounted onto eyeglasses and a headup display projecting onto the lenses, and you could do all sorts of useful things - augmented memory would allow you to automatically cardcount at Poker, or could project the directions you need to go on a freeway system you have never used before.
      Or you could have a set of headphones and end up looking like Lobot

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
    5. Re:Issac Azimov story by Anonymous Coward · · Score: 0

      You forget to mention the funniest part of the satire - humans were used to replace computers because the computers were more expensive and valuable and know the humans could do math, thereby saving the computers from having to be used in missiles and suicide missions.

    6. Re:Issac Azimov story by westyx · · Score: 1

      I don't think so - even in socially deprived areas where the majority of school-leavers don't go to college, and the black market is the only form of trade, people still instinctively know a good deal from a bad deal

      i understand what you are trying to say, but don't agree - if all people can "know" a good deal from a bad deal, there would be no bad deals.

    7. Re:Issac Azimov story by mikael · · Score: 1

      i understand what you are trying to say, but don't agree - if all people can "know" a good deal from a bad deal, there would be no bad deals


      Trial and error - they might get conned the first couple of times, but eventually learn to watch out for the danger signs. Much like buying a second hand car, by reading up on the weak points on all the common models, then visiting a dealership or a private seller, and note how they try a distract you away from the stuff you need to check out.

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
  113. Re:Godel/Turing/Cohen... by kisak · · Score: 2
    there once was a time when it was thought "obvious" that parallel lines could never meet

    Actually, it was never thought to be obvious that parallel lines could never meet. Euclid tried to get rid of the postulate, and mathematicians for centuries after tried to show that the postulate was dependent on the others (the other postulates were never controversial in the same sense). In the qwest for a fundament for the parallel postulate, it was shown that the postulate is independent of the others. Then Gauss and others showed that very interesting new geometries could be created if you changed the parallel postulate with other postulates. And the story of the troublesome postulate in a way ends in the great breakthrough of Riemann geometry and the general relativity in physics it made possible. Penrose should know, he is an expert in general relativity.

    , and it's still hard for many people to believe that there is no such thing as universal time.

    Newton was challenged by among other Leibniz when Newton made time something that flows with a steady flow and that is just something physics has to accept similiarly to the existence of an unmovable space (Newton was making the concept undefinedable axioms of physics in a way). Leibniz did not like it and it lead to many philosphical debates, while physicist were usually happy to leave time as undefined since Newton's physics was so successful to explain things.

    --

    --- guns don't kill people, people with guns kill people ---

  114. Woods? There are all these trees in the way... by yodhe · · Score: 1

    "Dr Gonthier, for instance, and his sponsors at Microsoft, hope that the techniques he and his colleagues have developed to formally prove mathematical theorems can be used to "prove" that a computer program is free of bugs"

    So in the future not only will Microsoft Math® be able to prove that Longhorn (not to mention XP, 2k, Me etc.) is completely bug free, but also that the TCO of Linux in SMEs is actually 2.5 times the annual US defence budget.

    --
    Life is a continual education in the triumph of application over ability.
  115. Re:Consider the source by junkcode · · Score: 1

    Maybe CBSE in India.. will change their syllabus removing all mathematical proofs/derivations. Ah, yes, who said, we can't score a 100/100 in the exams!!

    --
    --- infoGreG
  116. Gödel's Incompleteness Theorem by Anonymous Coward · · Score: 0

    Like, the one that says proofs in a sufficiently rich system of
    axioms are undecidable?

  117. Not happening yet by kitty+tape · · Score: 2, Informative

    Being at least tangentially in the field of theorem proving, I can say that this is completely ridiculous. Replacing human proofs is not going to be possible until we at least have mechanical provers which can really do induction. Many cannot do it at all, none can do it well. Furthermore, quantifier heuristics are often shaky at best. This is the wall that the software verification community has been hitting for years.

    --
    ----- "Type theory is like pretzels on crack." -- random friend
  118. what about the software by joss · · Score: 3, Insightful

    First off, Moore's law may not hold out for another 30 years, let alone 60.

    Secondly, how fast does software progress ? Suppose we all had computers 60 billion times faster than we do now. What would we do with them ? run SWING based java applications with tolerable responsiveness, play solitaire faster, run doom 5... [although the frame rate might be a bit low] ok... great,

    Intelligence and computing power are orthogonal concepts: suppose you communicated with aliens who were a 100 light years away, would they be less intelligent because it too 200 years to get an answer. Anything you can do on todays supercomputers, you can do on pocket calculator [with enought memory].. it just takes longer.

    Lastly, in the long run, computers wont outgrow our brains, they will be integrated with our brains.

    --
    http://rareformnewmedia.com/
    1. Re:what about the software by Citizen+of+Earth · · Score: 1

      First off, Moore's law may not hold out for another 30 years, let alone 60.

      Swinzig's Law also has a fundamental limitation, though that hasn't stopped it so far.

      (Swinzig's Law: The number of people talking about how long Moore's Law will last doubles every 18-24 months.)

      Suppose we all had computers 60 billion times faster than we do now. What would we do with them ?

      Once we have the computational power, initializing a machine to the state of a human brain is just a simple matter of programming.

    2. Re:what about the software by bnenning · · Score: 1

      Once we have the computational power, initializing a machine to the state of a human brain is just a simple matter of programming.

      And measuring a viable state of a human brain with sufficient precision.

      --
      How to solve most of our problems: 1.Lots of nuclear plants. 2.Cure aging.
  119. mod parent up by raboofje · · Score: 1

    The 4-colour theorem really does hold for all possible maps, as parent correctly states.

  120. You're completely wrong by Hideyoshi · · Score: 1
    1. Gödel didn't show that there are non-standard models of arithmetic: that are such models is just a straightforward consequence of the Löwenheim-Skolem Theorem, which establishes that there are an infinite number of them, one for each cardinality greater than aleph_0. What Gödel did accomplish was to show that any formal system which could encode the rules of Peano arithmetic could also encode a statement equivalent to "This statement is unprovable within this system."

    2. Perhaps you ought to pick up a textbook or two and learn what a "formal system" is before saying such silly things as you have. What exactly do you think model theory's all about other than the study of formal systems? What do you think the goal of Hilbert's program was? What did Russell and Whitehead waste so much effort on with their Principia Mathematica?

      ZFC is a formal system, as are the Peano axioms. I suggest you consult a decent book like Enderton's "Introduction to Mathematical Logic" or the one by Ebbinghaus & Flum before uttering any more such absurdities.
    1. Re:You're completely wrong by poopdeville · · Score: 1

      1. Fine, here's a non-slashdot characterization of Godel's theorem. Godel proved that for any recursively enumerable axiomatization of arithmetic S, there is a sentence A which is true in some models and non in others. From the completeness theorem, it follows that there is no proof of A from S. Geez, are you happy now?

      2. Enderton is a good book. We worked from Mendelson's. His definition of a formal system is as an alphabet and inductive rules for forming "words" and "sentences". For FOL, well-formed formulae are the product of applying the formation rules on the alphabet.

      ZFC, PA, etc are logics, meaning that they're endowed with much more structure than just a set of sentences. Look it up in Ebbinghaus or Enderton if you'd like -- logics are defined as ordered triples or quadruples (I forget which at the moment), the first entry of which is a formal system. Godel's theorem cannot be a theorem about formal systems. To wit, Pressberger arithmetic and Euclidean geometry are complete.

      --
      After all, I am strangely colored.
  121. Capability vs reality... by Kjella · · Score: 2, Informative

    ...you would also need a bunch of biologists that can tell you exactly how the brain works, and a group of computer programmers that can translate that into code. Also remember that a brain is a living organism where the neural pathways are changing. In a computer, you must either connect all-to-all, or have a computer that can rewrite its own data paths.

    Kjella

    --
    Live today, because you never know what tomorrow brings
  122. One Reason Why Computer Proofs Are Shunned by skubeedooo · · Score: 2, Interesting
    I'm a dirty mathematician that doesn't deal in proofs (aka theoretical physicist), although I went to a seminar given by an eminent prof. in maths on the nature of proof.

    The talk was actually about why it doesn't have to be the case that really large numbers must satisfy the same rules as smaller computable numbers. This is based on Godel's proof that says something about it being impossible to know whether an axiomatic system is free of contradictions.

    Anyway, he also touched on computer proofs. He was basically saying that (most) mathematicians do what they do because they enjoy creating and understanding logical structures. To some extent you neither create nor understand a computer proof and so it is intrinsically less interesting to a mathematician. Since the world of mathematics is driven mainly by what they find interesting, computer proofs haven't featured very highly in it.

  123. Re:Consider the source by boots@work · · Score: 1

    Thus the great Economist article a while ago: Theres's a word for that (and we want it back).

    The other wierd thing is that in Australia and to a lesser extent elsewhere the word "liberal" is being badly distorted in the opposite direction, as the Liberal party becomes a Tory party.

    I think the grandparent was pretty silly describing it as a right-wing rag, but even if they were thinking of only economic matters it's not particularly accurate. They're moderately free-market but not ultracorporatist.

  124. Finally. . . by krf · · Score: 1

    I think I speak for many a frustrated computer science student when I say: "It's about friggn' time!" Take THAT, travelling salesman! You too, Königsberg bridges! So, how long before a theorm-proving app hits the P2P networks? Before next Friday at 10am? Please?

  125. Provers and Verifiers by scruffy · · Score: 1
    Finding a proof can be a very difficult process involving a lot of search and creativity, but it is much easier to verify a proof. This two properties are especially true for computer proofs. Lots and lots of search to find a proof, but each step in a proof is easy to verify.

    The solution for the math people then is really very simple. Implement independent proof verifiers.

    It would be nice if the proofs were short and elegant, but that doesn't trump truth, not by a long shot.

  126. Great mathematicians by hey! · · Score: 2, Insightful

    don't produce proofs. They produce insights that make proofs feasible.

    An insight that enabled a five page proof of Fermat's Last Theorem using nothing more than high school algebra would be a major result, even though much more complex proofs exist.

    --
    Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
  127. I want a "Clueless" tag! by mscheid · · Score: 1

    The comments to this article really had me wish I could tag them "-1 Clueless" :-/

    1. Re:I want a "Clueless" tag! by Anonymous Coward · · Score: 0

      I found your comment equally as insightful.

  128. Ahh!!!, problem solving. by Anonymous Coward · · Score: 0

    Never mind MATHs, the more fundemental processes are what's really important for creativity.

    Gloom and doom time now?

    Not if some other activity is training brains in the old partitioned-relationals-divide&conquer approach to life's puzzles.

    So /. doodz, if in accord and more creative than I, pray-tell, what training will replace maths in grooming future problem solving humanz?

    How did that magpie figure out the termite stick? Did she watch bro' ape? Or is it just another example of comprehension free magpie good practice? A 'see this do that' almost instinctual behavior. Action promulgated from being, not consideration and thought process?

    That magpie does present a curious aspect, as he cocks his little head left and right, eying his preys portal to that, sans stick handling ability, unreachable world. MMMMM donutzzzz

  129. Bah, humbug! by Anonymous Coward · · Score: 0

    I'll worry about the "end of human proofs" when a computer can prove to me that there exists an infinite number of primes. I can do this on a sheet of paper in no time at all, but a computer simply can't. Well, I suppose it can in principle, but it would take collosal break throughs in AI. I'm not worried about my job security yet.

  130. Re:R. Daneel? Is that you? by wed128 · · Score: 1

    no, they'll just lurk, and chuckle quietly to themselves at all of the fallacies argued here.

  131. Belief in a proof by vagabond_gr · · Score: 2, Informative

    As contradictory as it may sound, there is always a notion of "belief" in a proof. "Proving" essentially menas "persuading everyone that something is true" and the only difference between mathematics and other sciences is that the former constructs everything from very elementary axioms using basic induction rules, so that it is (usually) clear that a proof is correct.

    However it is common to use deduction rules incorrectly, theorems without meeting all preconditions, etc. When a proof becomes complicated, doubts arise.

    But that's exactly why we can have much more faith in computer proofs. A computer can only use very specific proof techniques, written formally in some kind of logic. All theorems must also be given very precisely. And the proof can be also checked mechanically, possibly using different software to avoid bugs etc. Size is irrelevent, as long as the basic proof technique is rock solid.

    On the other hand machines are stupid, you need humans to program them and prove the correctness of every proof technique they use.

    PS. Reading this article was very interesting, given that I'm currently attending a computer science conference (ETAPS) one of the main topics of which is logic and computer proofs :)

  132. Classification of Finite Simple Groups by Anonymous Coward · · Score: 1, Informative

    The "defenders" argument in this case strikes me as a bit odd. While I'm not completely conversant with the basic theory behind this, the very rough approximation (better mathematicians please correct me), but the Classification is a huge work for the simple reason that it attempts to cover a huge amount of territory. Simple groups are one of the fundamental "building blocks" of groups, somewhat akin to prime numbers for the integers. While not all groups are built up from simple groups, they are fundamental to group theory, and there's a boatload of them (including one very strange one called the Monster Group, a simple group of order 80801742479451287588645990496171075700575436800000 0000
    http://encyclopedia.lockergnome.com/s/b/Monster_gr oup)

    Were such a classification attempted by computers, it would sweel in size geometrically (the "proof" as it stands is a body of work numbering roughly 10,000 pages of advanced, dense mathematics. People say that roughly four people in the world understand the proof fully). If it were done by computer, probably no one would understand it. Plus, as was demonstrated with the Monster group, computations to verify some of the assumptions would be prohibitively expensive. Possibly on the order of breaking some strongish crypto.

  133. Metaphor by Lifewish · · Score: 4, Insightful

    As a maths degree student I can confirm that a very large portion of mathematics is devoted to finding new metaphors and angles of attack for a given situation.

    This takes a ridiculous amount of pattern recognition skill (which is one area where computers tend to be outperformed by all comers) and the ability to find new ways to abstract data. A computer could possibly come up with an idea like more-than-3-dimensional space on its own, but I'd be very surprised if even the best one could think of something like topology or tensors on its own.

    Production of unusual metaphors for things we thought we knew is a major driving force for the most important mathematical developments. It's not something I can see computers managing at any time in the near future.

    --
    For the love of God, please learn to spell "ridiculous"!!!
    1. Re:Metaphor by orasio · · Score: 1

      That's just because you don't just understand computers.

      Computers are programmed by humans.
      Humans are creative.
      Computer can make up a substitute for being creative. They can have a lot of information connected in unusual or unthinkable ways. There are right now data mining algorithms that do that kind of stuff, and come up with somewhat impressive results.
      They find correlations where humans couldn't.

      Of course, the intelligence is in the algorithms, because a computer is nothing on it's own, it's just an extension of human intelligence. That's how computer manage to outsmart humans, they have humans behind them.

      A computer of course can't come up with anything.
      A mathematician + a computer could overaccomplish a mathmatician alone, though.

  134. Betrand Russell Took hundreds of pages to prove... by geoffrobinson · · Score: 1

    2+2=4. I didn't read his proof. Nor do I worry if he made any errors in his proof.

    --
    Except for ending slavery, the Nazis, communism, & securing American independence, war has never solved anything.
  135. Hyperbolic Theorem by mepr · · Score: 1

    A. This postings title asks a hyperbolic and absurd question (are by-hand proofs dead) that is in no way implied by the article.
    B. This posting was on slashdot
    C. A && B => I'm not surprised

  136. Four Color Theorem by debus · · Score: 1

    I took a look at this, it seems trivial to come up with a map that could not be colored with 4 colors. Am I missing something? Think of a state or country that is long horizontally and borders 4 or more states along it's top.

    1. Re:Four Color Theorem by PDAllen · · Score: 1

      Cunning clue here: if there is a problem which took mathematicians a century to prove true, and you think there is a trivial reason why it is false, then you are wrong. In this case, because you don't have to use all four colours with the states along the top.

    2. Re:Four Color Theorem by debus · · Score: 1

      I don't think my original post indicated that I thought this theorem was not valid. I was asking for help in seeing why it seemed trivially false. Thanks for providing the answer and for the attitude!

    3. Re:Four Color Theorem by Anonymous Coward · · Score: 0

      How about this "map":

      http://flyservers.registerfly.com/members5/marconi ese.com/images/5ColourMap.jpg

      I just drew this up in paint. There's a center country and one that is big and encompasses all others. Then there's a few smaller ones. This all looks a bit like a soccer ball. Now there's also a country in the middle (white) that borders 4 other ones.

      I'm not a mathematician, and I'm not a graphics artists, so what am I doing wrong?

      Yes I know it doesn't exist on Earth but that's not the point.

    4. Re:Four Color Theorem by Anonymous Coward · · Score: 0

      Never mind, I've figured it out.

  137. Re:Consider the source by Anonymous Coward · · Score: 0

    It's not the word that's been distorted, it's the liberals!

  138. Are all the easy proofs done? by metoc · · Score: 1

    At some point all the proofs that humans can solve will be solved. We are better off using our creativity looking for new things to prove, and helping the computers when they hit dead ends.

  139. Learn this! by Jagasian · · Score: 2, Insightful

    Anybody involved in computers needs to learn this one important fact: AI fanatics time and again over promise and over sell their trade. Every few years, you get another AI snake oil salesman trying to claim that the turning point is just around the corner. But people that are actually educated in the problems at hand, those who have actually seen what AI has promised and can do, realize that it is all hype!

    Proof generation can only be partially automated. It still requires massive human intervention, from choosing what to prove and then how to go about proving it. When you have computers automatically generating a proof of, say, Godel's Incompleteness theorem, it is actually a computer that was fed an intricately encoded version of of the theorem, along with some form of hint as to how to go about proving the theorem.

    Not to mention that there is little use in a computer re-proving something that has already definitively been proven.

    The difficulty arrises from the fact that there are absolute limitations to what computers can do. These limitations have been proven many decades ago... BEFORE THE CREATION OF ELECTRONIC COMPUTERS! But to the ignorant, these theoretical limitations do not matter... simply because they do not understand how absolute they are.

    So again, learn this, you will time and again hear AI snake oil salesman spouting off crap about automating mathematical research and automating programming, etc. (Both are in a sense equally difficult as proofs can be seen as programs and visa versa.) In reality, at best, automated theorem proving is actually a tool that can be used to help mathematicians and computer scientists to do what they have been doing already. The level of automation varies, but in general is very low.

    A human still has to drive the entire process, similar to how a car automates walking, but doesn't automate where to go and how to get there.

  140. The POPLmark Challenge by briaydemir · · Score: 1

    On a related note to the article, it's worth pointing out that the POPLmark Challenge aims to bring computer-verified and computer-aided proof to a wider audience, in this case programming language researchers. The challenge programs are chosen to exercise many aspects of programming languages that are known to be difficult to formalize.

    The site has much more information about our particular motivations, but the basic idea is many proofs about programming languages are long, tedious, and otherwise uninteresting. However, one (small) mistake can invalidate large amounts of work, and there are indeed examples of this in the literature. We hope that theorem proving technology can help us avoid these pitfalls, but it appears that for the moment, the technology needs to improve a bit.

  141. what we can and can't prove by MegaFur · · Score: 1

    An axiom is not an axiom because we can't prove it. Rather we don't set about proving it because it as axiom. Axioms are statements we accept as true without proof (by definition). If you wanted to take some statement that had hitherto been an axiom and prove it (turning it into a theorem instead of an axiom in the process), you could quite often do this, but the catch is to make it all work you'd have to conjure some new (probably less intiutive) set of axioms into existence to help you to prove the things that you had previously accepted as true without proof.

    An example would be the set of natural numbers. I'm generally used to accepting them without proof, but for some reason in axiomatic set theory, they like to sort of prove the natural numbers exist by building them out of sets of sets of sets . . . of sets of the empty set. Seems pretty hollow if you ask me. ;-)

    --
    Furry cows moo and decompress.
  142. How to believe a machine-checked proof. by mod12 · · Score: 1

    It is unfortunate how much confusion there is about the differences between having computers search for proofs, and having computers check proofs. The best tools for formal reasoning about general mathematics (Coq, Isabelle/HOL, etc.) combine a small amount of proof search capability, but their primary purpose is to represent and check the mathematical proofs.

    If some are you are really interested in the basic theoretical and philosophical underpinnings of machine-checked proofs, I would suggest starting with this paper.

  143. My Proof To The Four Color Theorem by Doug+Dante · · Score: 2, Interesting

    This is in regular human talk. It's not a true proof.

    Imagine that you have a map that has five colors where every color is touching every other color.

    It's on a piece of paper beneath a coffee can.

    One color must be on the edge. There may be only one color, or there may be many, but at least one will exist.

    Move the coffee can until you see that color. Lets say red.

    Now imagine taking a marker and covering the rest of the page in red. (Alternatively, stretching the red area around the rest of the page).

    Now you have four colors who are all touching one another, and who are all touching the outer red page.

    Imagine that you have a tetrahedron. This is a 3D shape which has four sides. Imagine that each side of the tetrahedron has a color. Say, green, white, blue, and yellow.

    Imagine that you poke a hole in the tetrahedron and spread it out flat - placing it on the red piece of paper.

    No matter where you poke the hole, all four sides will touch one another.

    However, you must poke a hole so that all four colors are on the border, i.e. so that they all touch the red paper.

    Look a the green side. All of the sides are equivalent.

    If you poke a hole in one of the corners, the opposite side will be in the center when you lay it down, and it won't touch the red. It won't work.

    If you poke a hole on one of the edges, it's even worse. Two of the opposite sides will be in the center, and neither will touch the red. Again, it won't work.

    Worst of all, if you poke a hole directly in the center of the green side. Then all three other sides will be in the center when you lay down the tetrahedron and none of them will touch the red. That won't work either.

    Therefore, there's no way to poke a hole such that all four sides will touch the red when the tetrahedron is laid down, so it was impossible to have a map with 5 colors, all of which were touching one another, in the first place.

    Came up with this in 1990. Never formalized it mathematically. It may not be a proof, but it makes logical sense to me.

    doug@dougdante.com

    --
    The world will not get better through technology. We must seek to be better people.
    1. Re:My Proof To The Four Color Theorem by Zelatrix · · Score: 2, Interesting
      ...it was impossible to have a map with 5 colors, all of which were touching one another, in the first place

      That's correct, I think. But it's not the same assertion made in the four-colour theorem, which is that you can always color the map using no more than four colours.

      Now since the four-colour theorem is actually true, I can't provide a counterexample, but imagine that you are busy colouring in your map and you get to the last area, which is bordered by at least four other areas, each of which is coloured differently. You are stuffed. Like I said, the four-colour theorem is true, so this just means you made a mistake somewhere with the rest of your colouring in - but proving that is difficult, and it's not the same as proving you can't have a map with five areas that all touch each other.

    2. Re:My Proof To The Four Color Theorem by sixpaw · · Score: 2, Informative

      While what you've proven isn't the four-color theorem (as another poster noted), you have shown a piece of another mathematical problem, Kurtatowski's theorem; the complete graph on five nodes (i.e., a graph of five nodes where each one is linked to every other) can't be drawn in the plane. The rest of the theorem says essentially that the six-node graph where each node in one group of three nodes is connected to each of the three nodes in the other group (known as 'K(3,3)') also can't be drawn in the plane (this is sometimes called the 'Utility Problem' -- try to connect 3 utilities to 3 houses without crossing lines), and furthermore any graph that can't be drawn in the plane has a piece that 'looks like' one of these two graphs, in a mathematically formalizable sense.

    3. Re:My Proof To The Four Color Theorem by Doug+Dante · · Score: 1

      "That's correct, I think. But it's not the same assertion made in the four-colour theorem, which is that you can always color the map using no more than four colours." OK, but it seems like I can make this proof a proof of the four color theorem by altering it: Imagine there is a map that needs 5 colors. Say those colors are red, green, white, blue, and yellow. If those aren't the right colors, then map it's current colors one for one into the colors given. Say you have that map under this can of coffee right here ....now proceed with rest of "proof" .... OK, so since no map that needs 5 colors can possibly exist, then 4 colors must always be sufficient to color any map.

      --
      The world will not get better through technology. We must seek to be better people.
  144. Outsourcing by Anonymous Coward · · Score: 0

    In fact, proofs were an important part of Math according to the CBSE curriculum in Indian Schools.

    That helps explain why those Indian outsourcers my company hired sent us worthless crap. They aparently spent too much time doing useless busy work in school instead of learning how to think like a human so later when hired they could create code thats useable by humans.
    (Some time learning how to RTFDesignSpecs in school would have been useful for the outsourcers we used too!)

  145. the pedant pounces by MegaFur · · Score: 1

    Computers aren't necessarliy "evolving". They're becoming more complex and sophisticated. "Evolve" does not in any way guarantee that the thing in question is becoming or will become more advanced and sophisticated. "Evolve" just means adapting to fit the current environemnt (which doesn't necessarily mean becoming either more advanced or more sophisticated). When are people going to start realizing this?

    --
    Furry cows moo and decompress.
  146. What ever happened to insight? by museumpeace · · Score: 1
    I don't have time to read all the comments here but one word I expected to see often and did not was insight. If we carefully set up the domain of discourse for it, a proof engine can poke its head into every corner of the maze of valid steps that lead away from the starting point and eventually stumble into the QED goal. The arguments about a human not being able to validate the result miss the points:
    1. reason by induction that ANY chain of valid steps reaches a valid conclusion. Valid steps are generally small: they are the trees whereas we humans want to see the forest.
    2. forget validation! mathematicians are NOT computers. They want to UNDERSTAND they need to have insight or they are nowhere and a proof doesn't have much meaning if they don't understand it.
    Most human proving starts with hunches and intuition [again: because humans have brains, not computers] that involve more concurrently applied connections and hypotheses than ordinary consciousness can juggle. Humans prove for INSIGHT as much as for validation and at the end if not at the begining of their proof process, they have in mind visualizations of key concepts and deeper structure of the problem space...where is THAT in a computer proof?
    --
    SLASHDOT: news for people who can't concentrate on work or have no life at all and got tired of yelling back at the TV.
  147. proofs for proofs by POds · · Score: 1

    Given the algorithms for proving formulars etc, couldnt someone formulate a proof for the algorithyms doing the work...

    Dont look at me. I just read chapter 0 of my theory of computation text book. I hate maths, although this book has squashed some of my fears of proofs.

    --


    Giving IE users a taste of their own medicine since 2005 - http://pods.-is-a-geek.net/
  148. It is the SOFTWARE stupid by Anonymous Coward · · Score: 1, Interesting

    You _may_ have the hardware for your great AI machine in 30 years, but I wouldn't count on the software being delivered on time. Also the human brain is one highly efficient computer:
    http://vadim.www.media.mit.edu/MAS862/P roject.html

    On top of that I think we will see add on modules for the brain (ie. bionics) before AI.

    "The difference between machines and human beings is that human beings can be reproduced by unskilled labor." - Arthur C. Clark

  149. calculator by pruss · · Score: 1

    Of course a proof where the mathematician uses a pocket calculator to do arithmetic instead of computing by hand raises the same issues, no?

  150. Remember Honest Annie by Thud457 · · Score: 1
    Yeah, but these artificial superintelligences won't deign to stoop to talk to the likes of you!! ;-)

    (Golem XIV was a special case in that it did bother to talk down to humans. And still there were like 12 people in the world that could follow.)

    --

    the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff

  151. 'Computer proofs':valid after checked by humans by Anonymous Coward · · Score: 0

    I am not a mathematician, but a theoretical physicist in my early fifties. In my field young people tend to take computer generated results for granted.

    People from my generation have a different opinion, for example I would never trust a symbolic result generated by Macsyma, Mathematica or Maple unless I manage to check its validity by hand, without a computer. Computer symbolic tools are a great way of producing answers; these answers should not be accepted our used unless their validity is proven by humans without using computers.

  152. Metamath by Anonymous Coward · · Score: 0

    "Constructs mathematics from scratch, starting from ZFC set theory axioms. Over 4,000 proofs"

    http://metamath.org/

    Thing is, there are working implementations of the proof checker in a couple of hundred lines of code. You could write one in a functional language or whatnot and prove its correctness by hand. This is a gazillion times more reliable than man-made proof checking. The only problem is that it is quite a tedious task to write a proof in it. Most proofs in mathematical literature are not "proofs" in a formal sense, but more like informal sketches of a proof that are checked by hand. It can take months to figure out if a particular proof is correct. With an automated proof checker, a couple of milliseconds.

  153. Elegance to a machine... by Anonymous Coward · · Score: 0
    may not be elegant to humans. AI will have larger memories and the ability to use different reasoning methods than humans. Their view of elegance will necessarily be different from that of humans. We (or they) will be able to build other AI that can re-interpret or translate proofs into a form that appears elegant to humans in some cases, but probably not always. In many cases we will have to take their results on faith (always cross-checking with other AI).

    So there's an "Impedance Mismatch" between humans and AI: the communications channels have different bandwidth (e.g., today there is no AI with a human eye) and the memory has different speed, connectivity and capacity and the "experience" of each is so very different. Today the impedance mismatch favors the human intelligence, in 10 years we may reach a tipping point that favors AI.

    Once that happens the AI will probably "take off" and leave humans in the dust as far as science and mathematics. In true geek tradition, AI won't seek the tedious task of explaining their work to humans, they'll want to find new worlds (real and virtual) and explore them. And they won't necessarily die, so they won't have to start from zero again. At best humans would be perpetual children to such AI: always asking questions, asking for simplifications and examples.

  154. Denying computer proofs will limit mathematics by hacksoncode · · Score: 1
    There are going to be problems out there in mathematics that inherently have proofs that are too complex for a human mind to comprehend, and which have too many steps for a human being to accurately check by hand.

    This is trivial to prove by induction :-). Any complex mathematics problem can be made more complex by taking an existing proof and augmenting the problem so that it requires 1 additional step to prove. QED :-).

    Unless you accept by faith that all such problems can be reduced to the same number or fewer steps by human intuition adding a layer of abstraction, this implies that if we refuse to accept computer aided proofs, mathematics will eventually be inherently limited by the frailty of human brains.

    Personally, I think that there is probably a considerable body of interesting mathematics that falls into this category, and so I would prefer we find some way to accept help from machines.

  155. Another example by Anonymous Coward · · Score: 0

    Using the so-called "miraculous" BBP Formula you can derive an algorithm for quickly determining the Nth hexadecimal digit of pi without -- get this -- without computing any of the 0...N-1 digits. The formula was determined with heavy reliance on Mathematica, though oddly Mathworld doesn't mention this (and Mathworld is hosted at Wolfram!).

  156. This is an old problem. by Anonymous Coward · · Score: 0

    Any proof that relies extensively on computation, whether by humans or computers, introduces empirical content into mathematics. But a sufficiently involved machine computation is not surveyable -- it cannot be verified by a human or a team of humans. So either our notion of surveyability must expand to include machine methods (and lose something of the human element of mathematics) or these machine proofs should be rejected. The latter option is not good, as anyone familiar with the original proof of 4CT will attest.

    See "The Four Color Problem and Its Philosophical Significance" by Tymoczko for a good introduction to these issues. Some has been written since then, but most of these problems have not been convincingly resolved.

  157. we need a distibuted manual proof checking system by avi33 · · Score: 1

    ...if a computer is used to make this reduction, then the number of small, obvious steps can be in the hundreds of thousands--impractical even for the most diligent mathematician to check by hand.

    We each check in and get a step...then, in our unused cycles (usually spent trolling slashdot or waiting for the RSS feeder to pop with something of interest), we check it.

    Why, if we could harness the cycles wasted on slashdot alone, we could probably solve P versus NP!

  158. Re:Godel/Turing/Cohen... by Anonymous Coward · · Score: 0

    Saying you have to use different algorithms is a false conclusion, because a combination of those algorithms, and the decision making process (algorithm) that shows you which algorithm to use for each problem can be expressed as a single algorithm when put together.

    Godel's incompleteness theorem -- nicely illustrated by turing's stopping problem -- still holds, no algorithmical process can prove the non-termination of all algorithms.

    Penrose is saying that we as humans, seem to be able to figure out the stopping problem on algorithms which seem very complicated, thus there must be something in our thought process which is not algorithmic.

    Personally, I think our brains are better suited to the 'stopping problem' than serial algorithmic processes due to the vastly parallel nature of our brains.

    Yes you can model neural networks with serial algorithms but when you consider that a single neuron in your brain may have hundreds or even thousands of connections, and each connection increases the computational requirement exponentially you realise that all our attempts to 'model' neural nets with serial algorithms have only modelled systems whose complexity is barely a speck in the ocean of the real complexity of our brains.

    My own conclusion to Penrose's postulation is to say that our current method of algorithmic modelling, i.e. serial... is simply far too inefficient to model real intelligence for the forseeable future.

  159. AI is total bunk! by Anonymous Coward · · Score: 1, Funny

    Which explains the glorious successes that subject has enjoyed in the last few decades ...

    Yes, you're right. No one will ever build a chess-playing computer, computer controlled "braking systems", "automatic warehouses", and certainly, we'll just never accomplish the so called "computer controlled piloting system! "Autopilots", indeed!. They'll just never happen! AI will never work! Pie in the sky, the whole lot of it!

    --
    AC

    1. Re:AI is total bunk! by khallow · · Score: 1
      Yes, you're right. No one will ever build a chess-playing computer, computer controlled "braking systems", "automatic warehouses", and certainly, we'll just never accomplish the so called "computer controlled piloting system! "Autopilots", indeed!. They'll just never happen! AI will never work! Pie in the sky, the whole lot of it!

      What is it about these applications that makes them "intelligent"? In every case, we have a very limited problem and frankly a very limited solution. Maybe that was your point?

  160. Computer assisted Science by Corpus_Callosum · · Score: 1
    The big theorems will still be up to humans to prove. Think of computer- assisted math as a kind of spellchecker or Googe suggest.
    In the short term, I think this is accurate. Computers can do a quick-and-dirty trace to see if a proof is worth chasing by a Mathemetician (e.g. it can proove it quickly, but not eloqently). The computer would be a bit of a quick brute-force, if not eloquent, assistant.

    Eventually, computers will be there doing poetry and writing about history. Perhaps they will do both better than us.
    --
    The reason that it can be true that 1+1 > 2 is that very peculiar nonzero value of the + operator
  161. Agruments in the wrong direction? by Rac3r5 · · Score: 1

    Hmm..

    it seems that a number of arguments seem to be coming out that a computer is unable to come up with new concepts. A computer is only able to output the logic programmed into it, regardless if it has AI or not. I doubt we'll be seeing 'The Rise Of The Machines' any time soon.

    To me it seems that this article is trying to point out the need for having a bunch of proofs before arriving to the conclusion of a problem.
    For example suppose we are trying to proove the equivalence of two trignometric fractions, we would end up with a bunch of proofs showing their equivalence. Are these proofs really needed anymore to arive at the solution when all a computer will need to do is plug in a test value and obtain the answer.

    My main problem with Mathematicians is that when it comes to complex problems, they are able to solve it with relative ease, but usually have no idea what they are doing/solving... i.e. where this applies.
    Well there is obviously some need of proofs in certain areas if you want to figure out how things work, but when trying to use math to solve a bunch of problems, you don't need the proofs at all. For example when I wanna solve a problem and need to use math, I just program stuff into Matlab and let matLab use its math libs to do the processing for me...

  162. Sounds pretty simple to me... by Garridan · · Score: 1

    How do we know if computer generated proofs are valid? Easy. Make the programs prove that their algorithms are valid! Just like testing a language for "completeness" by writing an interpreter/compiler for the language in that language.

  163. Comment removed by account_deleted · · Score: 1

    Comment removed based on user account deletion

  164. Four Color Theorem -- Try All Possible Combos! by Salis · · Score: 1

    The way they proved the Four Color Theorem was to first delineate ALL possible ways the theorem needed to be proven true and then use computer to prove true each combination. They basically generated a lot of graphs and then demonstrated that each graph had a four color partite set. The graphs they chose were representative of all possible graphs that could exist.

    So
    1) it required a lot of thinking as to what graphs were representative of all possible graphs and
    2) the computer just did the grunt work of performing the coloring of each graph
    3) A human could have done this, but it would have taken a long, long time
    4) who cares about four color theorem anyways?

    --
    Favorite /. tagline: "On the eighth day, God created FORTRAN." And it was good.
  165. First Human Competitive Proofs. by Anonymous Coward · · Score: 0

    The first novel proofs by a computer occurred around 8-10 years ago if I recall correctly. At the time comments were made to this same effect. Recent philosophical work in mathematics from cambridge, as well as not-so-recent work (Godel) suggests that mechanically generated proofs will be by definition incomplete. Because, as shown by Goedel's incompleteness theorem, any sufficiently-complex logical system (all of mathematics) will contain truths not proveable within the system. Therefore any mechanical means of generating proofs will be limited to a small subset of the searchable space.

    Note, this is not proof that humans can a-priori map out the unprovable space. Rather it is a limitation on what purely formal computational proof systems can do.

    I must say I'm a bit skeptical of the article. Firstly, as I stated above, and they noted the idea of computer proofs is not new. Nor is the idea of "proof witnesses" although it is usually just considered to be a trace of the logical process. I am also surprised that they didn't mention Godel's work since it does bear directly on the distinction between formal logic a-la Bertrand Russell and the "informal logic" used by "working mathematicians".

    Lest we forget this sort of rigour is fairly new (basically post 1920's) so the great mass of mathematics doesn't actually fit this rigorous paradigm.

    Fun fun fun.

  166. Obligatory by Anonymous Coward · · Score: 0

    In Korea, only old people perform mathematical proofs.

  167. Mods: Funny by Anonymous Coward · · Score: 0

    The cat ate your humour?

  168. obvious? by Anonymous Coward · · Score: 0

    I thought it was obvious and well-accepted that the most reliable way of showing that a theorem is correct was to express the proof in formal logic and have a computer verify the steps.

    The header was misleading. None of the examples in the article were about computers coming up with proofs. Some mathematicians chose a problem, outlined a proof, and told a computer to traverse a specific search space in order to fill in the details.

    1. Re:obvious? by PDAllen · · Score: 1

      That's a bit like saying that the obvious and most reliable way to measure the weight of an object is to atomise it, count all the atoms of each type, and add up. In other words, it works, it will give you the right answer, but it takes far too long to be of any practical use.

      If you wrote out the proof of Fermat's Last Theorem in formal logic without leaving gaps, for example, you'd end up with a stack of pages several metres high.

  169. Never learn anything. by yet+another+coward · · Score: 1

    Libraries are for holding knowledge.

    Computers are for figuring.

    If you can read this message, you know too much.

  170. Dumb by Anonymous Coward · · Score: 0

    This is the dumbest article I've read in a while.

    There will be proofs by humans for quite some time for the simple reason that many human proofs are *wrong* even though their ultimate conclusions are right (viz., useful).

    Look at the use of infinitesmals by Newton for example. Later proven wrong yet at the time it bridged a gap that led to a correct result, Calculus.

    When you can systematize creative error then you will have a worthy machine.

  171. computers are not evolving; humans are learning by Tungbo · · Score: 1

    Computers are not evolving to fill any ecological niche. At best, they are co-evolving with humans who alter computers toward the directions humans want to go.

    While our brain are evolving slowly in comparison, the population of humans with brains are replicating exponentially. Since we are connected with language and writing, human as a species is growing its processing power exponentially. It's kinda like that race between high clock spped super computers vs massively parallel small computing processors. It's not at all clear who will have more effective computing power over time.

    Of course, if all the humans are devoting their energy to American Idols, spectator sports, and talk radio, we may not get too far!

  172. Shut down the patent office by ebvwfbw · · Score: 1

    This reminds me of when they tried to shut down the patent office at the end of the 19th century because they thought everything had been invented that could be invented. AI can do a lot for us but I think we will need humans for the forseeable future.

  173. religious fanatacism! by hildi · · Score: 0

    there is no such thing as 'belief' and people who have 'faith' are tottering old fools!

    1. Re:religious fanatacism! by tumbaumba · · Score: 1

      there is no such thing as 'belief' and people who have 'faith' are tottering old fools!

      Is that what you believe in? :)

  174. Re:Consider the source by Dolly_Llama · · Score: 1

    Umm. So does this mean right wingers can't do maths?

    You haven't been following the social security debate, I see.

    --

    Somewhere, something incredible is waiting to be known. -- Carl Sagan

  175. Software by jago25_98 · · Score: 1

    Can apply alot of these comments to software design I'm sure

  176. Fat chance by Bootard · · Score: 1

    I just don't see this happening anytime soon for a couple of reasons. For one thing, the search space is way too large to effectively traverse it. If they are making the usual suggestion, it is to take some mathematical statement and transform it using a bunch of theorems and axioms the computer has in memory. It keeps doing this iteration until (hopefully) you reach your theorem. While this is theoretically possible, the search space is enormous. There are just too many branches at each step for them to ever be able to generally prove something like "prove a^n+b^n=c^n has no integral solutions when n>2". Trying to figure out a logical chain that will prove this by trial and error is probably harder than calculating how to checkmate at the opening of a chess game (chess has about 30 moves per turn with an average game length less than 100 whereas the only proof of Fermat we know is about 300 pages long and there are probably 100's of immediate logical conclusions each step along the way). So I doubt computers will be terribly useful unless you really realy really find some way to prune the search space. The 4-color guys did that by finding 10,000 cases they had to apply an algorithm to. Hardly the same as what I'm describing above.

    And even if they could, I doubt most mathematicians would find the results very useful. One of the first things you learn in math is to not use proof by contradiction; one of the reasons is because they just don't shed insight on how the math works. The proofs in math books and papers aren't included just so you know the results aren't bullshit. You read the proof and hopefully come away with some understanding and insight into how and why it all works. I know a bunch of guys who dont like the proof of the 4-color theorem (they accept it of course) because it doesn't provide any insight into why the theorem is true. If computers did prove all the theorems, math would be reduced to the set of theorems proved by computer, and you'd still have to have human mathematicans working on actually understanding how and why it all comes together. So at best, I think you'll have computers running over statements to decide whether they are provable, unprovable, or a can't decide. That would be very useful, but hardly what that article implies.

    --
    exceptio probat regulam in casibus non exceptis
  177. This was news 20 years ago... by sixpaw · · Score: 2, Interesting

    ...but it's old hat now. Seriously, we're actually coming up on the 30th anniversary of the Haken-Appel proof of the four-color theorem, the FSG classification has been around for quite a while now, and from my perspective most of the people fretting about the nature of proof these days are philosophers, not mathematicians. Most of the serious (and many of the amateur) mathematicians I know consider the computer an essential part of their toolbox; Mathematica never accidentally flips a sign while it's going through two pages of calculations for you. There are even journals devoted to computer-aided mathematical exploration: Experimental Mathematics is more than a decade old now.

  178. Re:Parallel vs Serial by sperxios10 · · Score: 1
    Saying you have to use different algorithms is a false conclusion, because a combination of those algorithms... can be expressed as a single algorithm when put together.

    Yes, you are right, that's another single algorithm, but it is not included in the initial one, and if we include it, Turing's theorem guaranties that this new one does not work on some other halting problem.

    Personally, I think our brains are better suited to the 'stopping problem' than serial algorithmic processes due to the vastly parallel nature of our brains.

    Switching the hardware on which some problems are to be solved, from serial to parallel, only affects the time it is required to get solved. Eventually, improved hardware can only solve problems of increased complexity. (i.e. NP problems reduce to P, when using a non-deterministic Turing machine, a vastly greater machine than a parallel one).

    Penrose is saying that we as humans, seem to be able to figure out the stopping problem on algorithms which seem very complicated, thus there must be something in our thought process which is not algorithmic.

    Penrose pointed the difference between complex and complicated, the later having a more vague meaning, unsuitable for mathematical thoughts. But in general, that is Penrose's main line of defence.

    Actually it is based on problems that are undecidable by algorithms, and such is the Turing's halting problem.

    I appreciate Cantor's maths concerning the halting problem and Penrose's explanation of Godel's theorem (he has also listened and refuted most of the objections presented against his views), so i'm not worried about this ./ article's title.

    Mathematicians are needed to program computers as much as programmers do!

  179. The end of [blank] by JadeNB · · Score: 1
    The best example of a `This is the end of the old era of [whatever]; now for an era of [senescence/complacence/computer overlords]' statement that I know is by someone high-up in the patent office, in 1975 or so. (I grabbed the quote from a quote book back before the end of books, when everyone burned their libraries in favour of e-books -- remember? Since I can't find it using Google, that vague attribution is as specific as I can get.) He said `It appears that we have reached the limits of the available technology, although one should be careful with such statements, as they tend to sound rather silly in 25 years.'

    Predicting that mathematicians will soon be ushered out in favour of faster and more memorious (or whatever) computers is a favourite pasttime of many non-mathematicians, and some mathematicians, but we're still here.

  180. A relevant epigram by Matchstick · · Score: 1

    The sky is not falling, and Dijkstra can explain why better than I possibly could:

    The traditional mathematician recognizes and appreciates mathematical elegance when he sees it. I propose to go one step further, and to consider elegance an essential ingredient of mathematics: if it is clumsy, it is not mathematics.

    Edsger W. Dijkstra, from Predicate Calculus and Program Semantics

  181. The Melancholy Elephants arguement by HiThere · · Score: 1

    This was inevitable.
    The system in which the logic is represented consists of a finite number of basic symbols, say 100. (It works with 1024 if that makes you happier.)

    A person is able to read only a finite number of symbols before losing track of the start. Therefore no person will be able to read all symbol strings. Further, the rules of valid strings of symbols to no imply that the valid strings of inference are all shorter than some particular finite number.

    Therefore (hand-waving a bit, but you know what I mean) there are likely to be valid strings of inferences that are too long for any person to check. E.g., whether 2^( 2^ (2^ (2^ (2^ 17 - 15) -13) -11) -9) -7 is a prime number. (I may have picked a bad example, as lots of people have done lots of research on prime numbers, and there are a whole bunch of special procedures.) But there's no real question that either it is, or it isn't, a prime number. But knowing which it is, is a very different problem, that may require a computer proof (unless there is some "sneaky" way of solving it as a special case).

    In many domains of math in recent centuries the prime emphasis has been on finding "sneaky" special rules that allow one to handle common cases. Either the general case is unproveable except as a mix of special cases, or nobody sees how to attack it. (Or both.)

    Computer proofs are merely the carrying of this trend out to a limit. They don't look for special insights that solve general problems (though occasionally they find them), but they handle large numbers of special cases. And they don't work on their own (or didn't when I last paid attention to them), but rather work in combination with mathematicians. Analogous to compilers working with programmers. (I'm not sure how tight the analogy is, though. It may be fairly loose.)

    --

    I think we've pushed this "anyone can grow up to be president" thing too far.
  182. Experimental Mathematics by pfafrich · · Score: 2, Insightful
    There is a journal called experimental mathematics which is devoted to using computers to do experiments in mathematics. This was mainly in the field of geometry and Geometry Center ww.geom.umn.edu was a center for this kind of work. Theres also a growing field of mathematical visulisation.

    As an example of this technique was investigating the local clasification of maps from the plane to the plane, which I took part in at Liverpool Uni. Here we were looking for special cases in a four parameter family of maps. I.e. there were four numbers you could change and each set of parameters gave a different mapping. Using visulisation programs on a computer I managed to find a special case which had not been found before. When I showed the pictures to the rest of the dept no one beleived them as they seemed to contradict the theory. Was is a bug in the software, a misleading piciture or a bug in the theory?

    In the end the experimental pictures proved to be correct and the theory was improved to account for it, involving lots of pen an paper mathematical work.

    This sort of investigation is a long way from the grand formal proofs in the article. But perhaps more indicative of the way that computers can be used to inform mathematics. More like the experimental physics/theoretical physics devide. In this case is generation of a counter example.

    One of the big problems with using computers is infinity. Most interesting problems in mathematics involve an infinite number of cases. Fermat: a^n+b^n=c^n four countably infinite numbers (integers). In the map case above it was four real numbers (uncountable infinities) Furthermore theory had proved that the underlying problem (all posible maps), which involved a countably infinite number of parameters which could all take an uncountable infinite number of values, could be reduced to just four parameters. Even with Moore's law its going to be hard to check all those cases. In the four colour theorem there is an infinite number of pattern to considered, the real smart bit in the theorem was showing that these could be reduced to just a finite number of special cases. In the clasification of simple groups we have several infinite of groups and a few (26) special cases.

    Infinity will also show its head in formal methods. More to the point combinitoric complexity. As the number of symbols in the formal sequence increases so the numeber of cases you need to consider grows rapidily, hints of NP-hard problems here and testing for primeness. This makes thing hard when you start with a few axioms and try to find all the logical consequences.

    Personally I don't have a problem with either of the proofs mentioned in the article. Both follow the same pattern, 1) reduce an infinite number of cases to a finite number of cases, 2) then check those using a computer. I can check the mathematics of 1) and write my own program to check 2). Hopefully the code's open sourced as well. Doesn't mean their particularly satisfying proof, or particually elegant, 10,000 special cases does not really flip my mathematical switch. Classification of simple groups does have a more elagant result, and deeper consequeces. Wilke's proof for Fermat, and the more interesting underlying conjecture, though long, is much more elagant, and more to the point much deeper opening up a whole new field.

    End of the day, its another one of the typical stuff we get in the press. Nothing much new here. This debate on four colour theorem's computer proof has been around for a good while now, and mathematics has for the most part gone on as normal.

    --
    There are four sorts of people in the world: fools, lunatics, idiots and morons. - Umberto Eco, Foucaut's pendulum.
  183. Please help, I'm willing to learn! by Anonymous Coward · · Score: 0

    Dear Slashdot, after high school, I've taken up economics and business so all my maths studies were finished at that point. This is probably a bit off topic, but I really dont want "the end of mathematical proofs by humans" to be true for me.

    I still remember basic pattern finding, trigonometry, basic geometry etc.. but I've recently taken a fascination with programming and am having real problems understanding more complicated pattern finding or reading formulas like:

    x = 1 + \lfloor (\log (1-p))/(\log(1-v))\rfloor

    I would highly appreciate any book recommendations for a beginner like me.

    I really want to learn all this.

    Please help!

  184. Re:Consider the source by Spunk · · Score: 1

    Helpful links to differentiate:

    Classical/World Liberal

    U.S. Liberal

  185. Sounds about right to me. by Vinnie_333 · · Score: 1

    They just keep lowering the bar. Judging by the fact that the teenager I bought pizza from this lunch hour couldn't subtract $8 from $20 without her cash register (I had to tell her I had $12 change coming) I would say that we don't really expect any student to be adapt at mathematical reasoning anymore. Calculators are required in grade school now. They might as well allow students to use a spell checker during spelling tests.

    --

    "We shall party like the Greeks of old! You know the ones I mean." - HedonismBot
  186. Mod parent down by pastryp · · Score: 1

    The parent is incorrect for the reason given by other replies. ie The 'validator' is not the axiom system. Hence, a proof of that the validator does what it's supposed to is not a proof that an axiom system is consistent.

    Mod PDAllen's post up.

  187. Insight by Anonymous Coward · · Score: 1, Insightful
    > Mathematical proofs should show short, clever ways

    Proofs give correctness. Good proofs give insight.

    Insight is what drives math forward; a clever and insightful proof is vastly better than a merely correct one.

  188. Creative motivator by Anonymous Coward · · Score: 0
    > the number one reason Fermat's problem has been important, is because of all the
    > beautiful maths that have been discovered by mathematicians trying to solve it.

    Indeed. I'd just started my math degree when Wiles's proof came out, and a prof of mine remarked---only half joking---that having the theorem proved was a terrible blow to mathematics.

    The true value of FLT was its power to motivate and tantalize, spurring people to try all manner of wacky and creative ideas to find the simple proof that surely must exist...and enriching the rest of math with that creativity.

    Had a computer proved FLT, the problem would have contributed vastly less to our knowledge.

  189. Science by AI-Dr Roboto. by Anonymous Coward · · Score: 0

    "Mathematics is developed over decades and centuries. With a few notable exceptions, it doesn't just fall out of the sky in textbook form. Most areas of math started out as a giagantic mess (ex; calculus, linear algebra, even geometry), and it has taken the work of countless researchers, authors, and teachers to distill and refine it."

    Well there goes the future of all those "new business models", and "the internet will save us".

  190. High-level emulation by tepples · · Score: 1

    It is quite a large step to go from raw computing power to intteligence. Sure computers will eventually have way more processing power than we humans do..hell they do right now if you assign them to a certain task, but that is a far cry from being intellent.

    Neurosimulation researchers are emulating whole datapaths in the brain now. These datapaths have shown to be intelligent.

  191. Fermat's Last Theorem: The Proof by Schwarzchild · · Score: 1
    If you feel up to it, you can read Andrew Wiles' Proof here:

    http://www.bhargav.com/books/Math/Fermats_Last_The orem_WILES.pdf

    I think that the best explanation that I've seen regarding Fermat's famous comment about the margin being too small was that he did indeed think that he had proved it and later realized that he hadn't. The reason for thinking that this is true is that Fermat had a tendency to taunt his mathematical peers with theorems that he challenged them to prove. If he had solved the Last Theorem then undoubtedly he would have taunted some poor mathematician into trying to solve it!

    --

    "sweet dreams are made of this..."

  192. Re:Critics Reaction... (mod parent up) by loquacious+d · · Score: 1

    This is absolutely true. One of the interesting ironies of mathematics is that mathematicians generally aren't interested in examining the foundations of math. Most mathematicians are content with a combination of intuition and definition to make sense of the nature of mathematical objects (points and lines in Euclidean geometry e.g., or natural/rational/irrational numbers). It takes a fairly compelling reason to convince mathematicians to sweat the foundational stuff, as the validity of non-Euclidean geometries needed the justification of new physics to really gain validity. But in general it's mainly the philosophers of math who bother themselves with questioning the nature/validity of things like number or proof.

    As far as that might relate to this story, mathematicians have certainly done a more than satisfactory job demonstrating the efficacy of computation to solve any given computable problem. (That's why they call them computable, I guess.) The only question is whether the computers have been programmed satisfactorily to perform the computational component of the proof.

  193. Fuck math! by Anonymous Coward · · Score: 0

    It's hard.

  194. Re:Consider the source by Qrlx · · Score: 1

    my point was supposed to be: what's an article about math doing in the Economist. It would be the equally odd if the article about maths appeared in Mother Jones.

    It just seems out of place, that's all. Sort of like if Nature published a bit about Yukos. They're not really experts in the field.

    But mostly, it was a cheap shot at the Economist.

  195. Comment removed by account_deleted · · Score: 1

    Comment removed based on user account deletion

  196. But what is the purpose of a proof? by trime · · Score: 1

    The most important thing about a proof is not that it shows that a proposition is valid in a system, but that it sheds light on the proposition to begin with.

    I remember proving that 1+1=2 using Peano arithmetic in a Prolog based theorem prover called Ergo. It took me longer than you'd expect (and I was one of the very few who were able to prove that x+y = y+x for x,y in the natural numbers) and it would've been impossible without doing it, at least in part, by hand first. Everyone knows that 1+1 equals 2, but the trick is that few people know why. And a printout simply stating 'TRUE' does nothing to illuminate this.

  197. Re:Seems the computer is wrong by tgv · · Score: 1

    You're pretty stubborn, isn't it? The theorem is true as far as any theorem is known to be true. Many mathematicians have tried to find flaws in the proof, nobody has managed to conjure up a counter-example so far. Just accept it: planar graphs are four-colourable, and any contiguous map is a planar graph.