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Mathematicians Team Up To Close the Prime Gap

Hugh Pickens DOT Com writes "On May 13, an obscure mathematician garnered worldwide attention and accolades from the mathematics community for settling a long-standing open question about prime numbers. Yitang Zhang showed that even though primes get increasingly rare as you go further out along the number line, you will never stop finding pairs of primes separated by at most 70 million. His finding was the first time anyone had managed to put a finite bound on the gaps between prime numbers, representing a major leap toward proving the centuries-old twin primes conjecture, which posits that there are infinitely many pairs of primes separated by only two (such as 11 and 13). Now Erica Klarreich reports at Quanta Magazine that other mathematicians quickly realized that it should be possible to push this separation bound quite a bit lower. By the end of May, mathematicians had uncovered simple tweaks to Zhang's argument that brought the bound below 60 million. Then Terence Tao, a winner of the Fields Medal, mathematics' highest honor, created a 'Polymath project,' an open, online collaboration to improve the bound that attracted dozens of participants. By July 27, the team had succeeded in reducing the proven bound on prime gaps from 70 million to 4,680. Now James Maynard has upped the ante by presenting an independent proof that pushes the gap down to 600. A new Polymath project is in the planning stages, to try to combine the collaboration's techniques with Maynard's approach to push this bound even lower. Zhang's work and, to a lesser degree, Maynard's fits the archetype of the solitary mathematical genius, working for years in the proverbial garret until he is ready to dazzle the world with a great discovery. The Polymath project couldn't be more different — fast and furious, massively collaborative, fueled by the instant gratification of setting a new world record. 'It's important to have people who are willing to work in isolation and buck the conventional wisdom,' says Tao. Polymath, by contrast, is 'entirely groupthink.' Not every math problem would lend itself to such collaboration, but this one did."

194 comments

  1. Mr President by Anonymous Coward · · Score: 5, Funny

    We cannot allow a prime gap!

    1. Re:Mr President by Anonymous Coward · · Score: 0

      We cannot allow a prime gap!

      All prime suspects are to be extraordinarly renditioned and sent to Guantanamo.

    2. Re:Mr President by Anonymous Coward · · Score: 0

      WOOOSH common slashdoters that are more than 50 years old, that is why I modded it funny! That quote is one of my all time favourite ones from Dr Strangelove the other one came from Major "Bat" Guano

    3. Re:Mr President by Anonymous Coward · · Score: 0

      I hate to break it to you but dr strangelove is hardly an exotic film to know among people under fifty.

  2. regarding collaborative efforts by Anonymous Coward · · Score: 5, Insightful

    sometimes its better to go it alone, then come back to the group with your results so that someone else may profit from them.

    sometimes its better to be a part a group in order to establish your ideas and discuss, then go it alone when the group holds you back.

    1. Re:regarding collaborative efforts by Russ1642 · · Score: 5, Funny

      Wow. That's like so deep man.

    2. Re:regarding collaborative efforts by Anonymous Coward · · Score: 1

      Yeah, sometimes doing A is good, but other times, doing B is good.

    3. Re:regarding collaborative efforts by NatasRevol · · Score: 2

      That's why C is always pissy.

      --
      There are two types of people in the world: Those who crave closure
    4. Re:regarding collaborative efforts by Anonymous Coward · · Score: 0

      Both, A, B, and C are pissy, but not really.
      That's D for you.

    5. Re:regarding collaborative efforts by Anonymous Coward · · Score: 0

      Both, A, B, and C are pissy, but not really. That's D for you.

      You fail English.

    6. Re:regarding collaborative efforts by Anonymous Coward · · Score: 0

      Me fail english? Thats unpossible!

    7. Re:regarding collaborative efforts by TeknoHog · · Score: 1

      That’s just like, your opinion, man.

      --
      Escher was the first MC and Giger invented the HR department.
  3. How to they prove that? by Anonymous Coward · · Score: 0

    Oh, nevermind...

  4. Nice work by Anonymous Coward · · Score: 5, Funny

    If they keep this shit up, pretty soon they will prove that every number is prime.

    1. Re:Nice work by pellik · · Score: 4, Insightful
    2. Re:Nice work by Anonymous Coward · · Score: 0, Troll

      And there in a nutshell is the whole anthropogenic global warming argument.

    3. Re:Nice work by ebh · · Score: 5, Funny

      3 is prime, 5 is prime, 7 is prime, 9 is bad data, 11 is prime, 13 is prime...

    4. Re:Nice work by Anonymous Coward · · Score: 0

      Except for the time scale.

      And the quantity of data samples.

    5. Re:Nice work by SleazyRidr · · Score: 1

      Wait, the infra-red spectrum of carbon dioxide is based on babies in anthropogenic nutshells? I'm confused.

    6. Re:Nice work by Anonymous Coward · · Score: 0

      "I'm confused."

      I think that's the goal.

    7. Re:Nice work by martas · · Score: 1

      Spoken like a true biologist -- "Based on 7 samples of 10000 dimensional microarray data, I have concluded that this gene causes all cancer in everyone!"

    8. Re:Nice work by almitydave · · Score: 5, Funny

      Seems like a good place for my favorite joke:

      An Astronomer, a Physicist, and an Mathematician have traveled to England for the first time to attend a conference and are riding a train through the countryside. Before long they pass a field with a single black sheep in it. The Astronomer says, "well look at that, in England, the sheep are black." The Physicist rebukes him, saying, "how can you make such a broad statement? All we know is that in THIS field, the sheep are black." The Mathematician shakes his head in scorn at both of them and says, "gentlemen, you are both making overly general assumptions. All we can says for certain is that in England there exists at least one field, containing at least one sheep, at least one side of which is black."

      --
      my, your, his/her/its, our, your, their
      I'm, you're, he's/she's/it's, we're, you're, they're
    9. Re:Nice work by Anonymous Coward · · Score: 0

      That is also the entire argument that gravity will continue to work tomorrow, and that the Sun will rise tomorrow (assuming you are not too close to poles and the weather lets you see it).

    10. Re:Nice work by ricketson · · Score: 1

      And the physics. Never forget about the physics.

    11. Re:Nice work by antdude · · Score: 1

      Proving FTW! :D

      --
      Ant(Dude) @ Quality Foraged Links (AQFL.net) & The Ant Farm (antfarm.ma.cx / antfarm.home.dhs.org).
    12. Re:Nice work by Anonymous Coward · · Score: 0

      ... at least some of the time.

  5. See Kuhn by TheloniousToady · · Score: 3, Informative

    'It's important to have people who are willing to work in isolation and buck the conventional wisdom,' says Tao. Polymath, by contrast, is 'entirely groupthink.' Not every math problem would lend itself to such collaboration, but this one did."

    History is rife with examples of the lone genius making a leap forward, thereby allowing the crowd to take it even further. See The Structure of Scientific Revolutions by Thomas Kuhn.

    1. Re:See Kuhn by Anonymous Coward · · Score: 0

      I'm not saying his leap came from aliens, but... it was aliens

    2. Re:See Kuhn by Anonymous Coward · · Score: 1

      Favourite quote re said crowd taking it further:

      I am not a Kuhnian.
      --Thomas Kuhn

    3. Re:See Kuhn by sfkaplan · · Score: 5, Informative

      Wait, what? If that's what you think Kuhn wrote, then you may need to go re-read the book.

      His central claim was not that lone geniuses make leaps, but that leaps can rarely be attributed so clearly to a single individual, moment, or event. The Big Idea of that book is that the process of scientific advance is much messier, and much more contextually dependent, then we are lead to believe in popular accounts. Often the so-called "genius moments" are a critical step, but not easily or correctly identified as such until after the fact, making it hard to know *which* insight was really the critical one.

      There's lots of dispute about Kuhn, but let's not make matters worse by incorrectly describing what he wrote.

    4. Re:See Kuhn by Anonymous Coward · · Score: 0

      It's ok... people hold onto the idea of lone geniuses like they do saints. They're one and the same mythology, for different ages. We tend to strip context away from progress, and ignore what we can't oversimplify.

    5. Re:See Kuhn by yusing · · Score: 1

      We should all go re-read Kuhn anyways. Because (thinking of the current state of cosmology for one) clearly we didn't get it yet.

      --

      "You must try to forget all you have learned. You must begin to dream." -- Sherwood Anderson

    6. Re:See Kuhn by Anonymous Coward · · Score: 0

      yes, that's why 70Million is the most important number here even compared to 600.

    7. Re:See Kuhn by TheloniousToady · · Score: 1

      Actually, I haven't read it yet. I only recently heard about it while reading a biography of Joseph Priestley. I hope to read the Kuhn book soon.

      Anyway, sorry if I got that wrong. I was just trying to further the always-erudite discussion here. To that end, thanks for setting me straight in the most condescending and pedantic way possible. ;-)

  6. Yawn. by Anne_Nonymous · · Score: 2, Funny

    >> which posits that there are infinitely many pairs of primes separated by only two (such as 11 and 13)

    Yawn. Call me when you find a set of primes separated by one.

    1. Re:Yawn. by beelsebob · · Score: 1

      Okay... Found them. 2 and 3.

    2. Re:Yawn. by somersault · · Score: 1

      {2, 3}

      --
      which is totally what she said
    3. Re:Yawn. by ChristW · · Score: 0

      2, 3

      Thank you, I'll be here all week...

      --
      09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0
    4. Re:Yawn. by magic+maverick+ · · Score: 0

      I've found a set of primes separated by one.

      {2,3}

      Do I get a Fields Medal for that?

      Also, mathematics is awesome. Even if I can't understand it.

      --
      HELP MY ACCOUNT HAS BEEN HACKED BY AN ILLIBERAL ART STUDENT SET TO DESTROY THE INTERWEBZ!
    5. Re:Yawn. by Anonymous Coward · · Score: 0

      2 and 3?

    6. Re:Yawn. by Anonymous Coward · · Score: 4, Funny

      I can do better: I can prove that there are infinitely many pairs of prime numbers p and q separated by zero!

      Here are the first few such pairs:

      (2,2)
      (3,3)
      (5,5)
      (7,7)

    7. Re:Yawn. by magic+maverick+ · · Score: 2

      Damn it. I got pipped to the post. And by a number of people, a number of minutes before me! I demand a recount.

      --
      HELP MY ACCOUNT HAS BEEN HACKED BY AN ILLIBERAL ART STUDENT SET TO DESTROY THE INTERWEBZ!
    8. Re:Yawn. by tommeke100 · · Score: 2

      they seem to be separated by a comma

  7. Factoring Primes by ebno-10db · · Score: 1, Interesting

    Will they ever learn to factor prime numbers though? I understand it's difficult, but solving it would save a lot of embarrassment when people misstate the problem.

    1. Re:Factoring Primes by mrego · · Score: 1

      Prime numbers are the scaffolding of the number system and all of nature. I am convinced that twin primes represent the spine or backbone of an understanding of prime numbers. If the mystery of twin primes fall, soon we will understand primes and then all of nature. And we'll be rich, evil, mad geniuses with unlimited power. Mhhhahahahaha

    2. Re:Factoring Primes by Anonymous Coward · · Score: 0

      > Will they ever learn to factor prime numbers though?

      It's easy: let p be a prime number. It's prime factors are: {p}

      HTH

    3. Re:Factoring Primes by Anonymous Coward · · Score: 5, Informative

      Factoring prime numbers is dead easy. Here's an implementation in Python:

      # factorize prime
      # precondition: the argument is a prime
      # if the precondition is not met, the result is wrong.
      # result: The factorization of the argument.
      def factorPrime(p):
          return [ p ];

      It's the factoring of composite numbers that is difficult.

      Actually, even factorizing composite numbers isn't really difficult. It's just difficult to do it in a way that finishes before you stop caring about the result. ;-)

    4. Re:Factoring Primes by NatasRevol · · Score: 2

      So much error. So much missing.

      {p,1} are the prime factors.

      --
      There are two types of people in the world: Those who crave closure
    5. Re:Factoring Primes by ebno-10db · · Score: 1

      we'll be rich, evil, mad geniuses with unlimited power. Mhhhahahahaha

      Sounds good, as long as we don't actually achieve it. The joy of being an evil genius is in striving, not succeeding.

    6. Re:Factoring Primes by Anonymous Coward · · Score: 3, Informative

      According to modern mathematics definition, 1 isn't a prime number because it is invertible. If you allowed invertibles among prime numbers then uniqueness of the factorization in primes wouldn't hold anymore as your example shows. We could have {p} {p, 1} {p 1 1}.

    7. Re:Factoring Primes by Anonymous Coward · · Score: 0

      Um, no:

      https://en.wikipedia.org/wiki/Prime_factor

    8. Re:Factoring Primes by ebno-10db · · Score: 1

      Either way, leave it to a mathematical genius to ruin a joke.

    9. Re:Factoring Primes by ObsessiveMathsFreak · · Score: 1

      It's the factoring of composite numbers that is difficult.

      Actually it's even easier

      def factornumber(n):
              return [ n,1 ];

      (And now I can't want to see how someone out pedantics-me in continuing this petty-up-man-ship thread.)

      --
      May the Maths Be with you!
    10. Re:Factoring Primes by ebno-10db · · Score: 2

      And now I can't want to see how someone out pedantics-me in continuing this petty-up-man-ship thread.

      Done before you posted - see upthread. Just as there's an Obfuscated C contest, Slashdot should have an "Ultimate Pedantry" contest.

    11. Re:Factoring Primes by Anonymous Coward · · Score: 0

      def factornumber(n):

      return [ n,1,-n,-1 ]

      If you aren't going to restrict "factor" to mean the prime factors, might as well go fully redundant and list all integer factors.

    12. Re:Factoring Primes by nayrbn · · Score: 1

      Mathematicians have already learned to factor primes numbers. For instance, consider the imaginary number i=sqrt(-1). Then we have 3=(2+i)(2-i), 5=(2+i)(2-i), 17=(4-i)(4+i), and so on.

    13. Re:Factoring Primes by nayrbn · · Score: 1

      Annnnnnddd... the first factorization is wrong. It should be 2=(1+i)(1-i).

    14. Re:Factoring Primes by SpaceLifeForm · · Score: 1
      The 'spine or backbone' of prime numbers is most certainly tied not to the twin primes, but the quad primes.

      I submit, that there are an infinite number of quad prime sets.

      [ P,P+2,P+6,P+8 that are all prime, aka, back to back pairs of twin primes]

      --
      You are being MICROattacked, from various angles, in a SOFT manner.
    15. Re:Factoring Primes by elfprince13 · · Score: 1

      Nope. 1 is not a prime.

    16. Re:Factoring Primes by Valdrax · · Score: 2

      That was done before you posted; see up-thread. Just as there's an International Obfuscated C Code Contest, Slashdot should have an "Ultimate Pedantry" contest.

      FTFY.

      --
      If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
  8. primes separated by one by xxxJonBoyxxx · · Score: 5, Informative

    Er...2 and 3. What do I win?

    1. Re:primes separated by one by MiniMike · · Score: 5, Funny

      What do I win?

      The tattered remnants of Anne_Nonymous's (probably not her real name) Geek Card, in a frame.

    2. Re:primes separated by one by bill_mcgonigle · · Score: 1

      A "misses the concept of infinity" patch to sew on your uniform.

      But we all know the final lower bound will be 42 anyway.

      --
      My God, it's Full of Source!
      OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
  9. blood sweat tears innocence by Anonymous Coward · · Score: 0

    all being confiscated, you can count #s on us but not much else

  10. Even lower? by srussia · · Score: 1

    Now James Maynard has upped the ante by presenting an independent proof that pushes the gap down to 600. A new Polymath project is in the planning stages, (...) to push the bound even lower.

    600 ought to be enough for anyone.

    --
    Set your phasers on "funky"!
    1. Re:Even lower? by OakDragon · · Score: 1

      A good joke, but I think you dropped some precision.

  11. Problem solving abilities by ebno-10db · · Score: 5, Funny

    Three people are asked to prove that all of the odd numbers are prime - a physicist, a mathematician and a programmer.

    The physicist goes first. "3 is a prime, 5 is a prime, 7 is a prime, 9 is a ... oops, experimental error, 11 is a prime ...".

    Next the mathematician takes a crack at it: "3 is a prime, 5 is a prime, 7 is a prime, and the rest by induction".

    Finally it's the programmer's turn. "3 is a prime, 5 is a prime, 7 is a prime, 9 is a prime, 11 is a prime ...".

    1. Re:Problem solving abilities by VortexCortex · · Score: 5, Funny

      // [VC 2013.11.20] Fix primary oddity error in prime oddity test.
      #define 9 015

    2. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      Next the mathematician takes a crack at it: "3 is a prime, 5 is a prime, 7 is a prime, and the rest by induction"

      This part of the joke is playing on the two* different meanings of the word "induction".

      This joke uses the kind of induction as used by empiricists: http://en.wikipedia.org/wiki/Inductive_reasoning

      In mathematics, a proof by induction has two parts. Part one is in your joke, the second part, the actual "induction step" where it is proven that what goes for n also holds for n+2, is missing. So this "mathematician" is not truly a mathematician: http://en.wikipedia.org/wiki/Mathematical_induction

      Yeah, I know, explaining a joke ruins it.

      *Two meanings of "reasoning by induction" that is, leaving others meanings like "electromagnetic induction" or "induction of childbirth" out.

    3. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      Thanks, Sherlock.

    4. Re:Problem solving abilities by jalopezp · · Score: 1

      It's not a programmer, it's an engineer. A programmer what is proof.

    5. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      Meanwhile, the politician says "If you vote for me, we will create a kinder, gentler society where *every* number can be prime!"

      captcha: counts

    6. Re:Problem solving abilities by ebno-10db · · Score: 2

      I know, explaining a joke ruins it.

      That point can't be overemphasized.

    7. Re:Problem solving abilities by ebno-10db · · Score: 1

      It's not a programmer, it's an engineer.

      You're right, I should have stuck to the original version. With the character as an engineer, it's a humorous error. With a programmer, it's more like what did you expect?

    8. Re:Problem solving abilities by ebno-10db · · Score: 5, Funny

      An interesting paradox. You're not a real programmer if you realized that define was necessary, but you are a real programmer if you obfuscated it using that archaic octal notation.

    9. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      Engineers don't prove things. They look them up in catalogs. They may just be stuck trying to find a prime number vendor that will sell them a 9.

    10. Re:Problem solving abilities by ebno-10db · · Score: 1

      They may just be stuck trying to find a prime number vendor that will sell them a 9.

      No, that's quite easy. You don't believe all those specs, do you?

    11. Re:Problem solving abilities by SleazyRidr · · Score: 1

      Explaining a joke always makes it better.

    12. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      A strange game. The only winning move is not to compile.

    13. Re:Problem solving abilities by KingMotley · · Score: 1

      Close, but the programmer would have likely introduced a spelling error.

    14. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      If you haven't seen a mathematician, or at least a math major, screw up induction, then you haven't been around math much. And I'm not talking about about empiricism, but the induction step of actual mathematical induction, where a common failure is to derive a proof that doesn't properly connect to the starting part or uses some assumption that doesn't carry through.

    15. Re:Problem solving abilities by Luyseyal · · Score: 1

      Archaic? I ran into that bug^H^H^Hnotation in JavaScript, of all things. Must be NEWWWWWWWW.

      -l

      /man that was an annoying bug to fix

      --
      Help cure AIDS, cancer, and more. Donate your unused computer time to worldcommunitygrid.org. Join Team Slashdot!
    16. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      I don't know about "better."

      Its like dissection: you learn a lot, but you kill it in the process.

    17. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      Finally it's the programmer's turn. "3 is a prime, 5 is a prime, 7 is a prime, 9 is a prime, 11 is a prime ...".

      The version I heard goes like this:

      The engineer says: "3 is a prime, 5 is a prime, 7 is a prime, 9 is a prime, 11 is a prime ..."

      Finally, the programmer writes a program to solve it: "3 is a prime, 5 is a prime, 7 is a prime, 7 is a prime, 7 is a prime ..."

    18. Re:Problem solving abilities by Anonymous Coward · · Score: 0

      Don't forget the engineer: 3 is a prime, 5 is a prime, 7 is a prime, therefore all odd numbers are prime.

    19. Re:Problem solving abilities by EETech1 · · Score: 1

      My first assembly program for the Atmel AVR gave me quite the headache debugging! The output would jump around randomly, and sometimes go backwards.

      My program worked fine if I put the data tables in hex, but if I tried to put them in (what I thought was) decimal all hell broke loose. Watching the code in the emulator, I couldn't figure out why the lookups were giving me the wrong numbers.

      I finally just made two data tables from 0 - 255, one in hex and one in decimal, and then programmed, and read back the flash and looked at the hex file, and the two tables were different!

      I was trying to make my code look nice, so I made all the data points 3 digits, then I had a nice easy to modify table in the editor. .DB 000, 000, 001, 001, 002, 003,..... .DB 009, 010, 011, 012, 013, 014...... .DB 092, 096, 100, 104, 109, 115......

      Really made my interpolation routine give some crazy results when it underflowed!

      Cheers!

  12. Summary by orlanz · · Score: 1

    Was it just me or did anyone else have a hard time following that summary? At first I thought it was Yitang Zhang who settled "a long-standing open question". But the first sentence is actually talking about the eight - James Maynard.

    So in summary, if a pair of primes is defined by one following the other, it was theorized that we would find an infinite number of such pairs separated by 2. Various people have proven that gap to be from 70m, 60m, 4680, and now 600. Thank you James Maynard.

    1. Re:Summary by Anonymous Coward · · Score: 1

      Zhang proved it's finite. The others have just lowering the finite number with newer proofs.

    2. Re: Summary by KramberryKoncerto · · Score: 1

      Didn't you see the phrase "lesser extent"?

    3. Re:Summary by wonkey_monkey · · Score: 2

      At first I thought it was Yitang Zhang who settled "a long-standing open question". But the first sentence is actually talking about the eight - James Maynard.

      It was Yitang Zhang who settled the original long-standing open question - that being, is there any number such that you will always find pairs of primes separated by that number or less. The ultimate goal is to solve the twin prime conjecture - bringing the number in question down to 2.

      Your own wording is a little confusing - I'm not sure who the "eight" are, or whether "eight - James Maynard" refers to seven mathematicians, in which you couldn't describe them all as "an obscure mathematician" ;)

      His finding was the first time anyone had managed to put a finite bound on the gaps between prime numbers

      This (from the summary) is a bit of an ambiguous way to put it - it's not a bound on gaps per se, because there could still be consecutive primes separated by 70 million (such as 70,000,000! and it's neighbour), but there will always be another pair further along separated by less.

      --
      systemd is Roko's Basilisk.
    4. Re:Summary by wonkey_monkey · · Score: 1

      (such as 70,000,000! and it's neighbour)

      Err, ignore this. Getting confused.

      --
      systemd is Roko's Basilisk.
    5. Re:Summary by Kjella · · Score: 5, Insightful

      Was it just me or did anyone else have a hard time following that summary? At first I thought it was Yitang Zhang who settled "a long-standing open question". But the first sentence is actually talking about the eight - James Maynard.

      No. Before May 2013 there was no proof on an infinite pair of primes being a finite bound apart.
      - May 2013: Zhang, bound 70 million
      - End of May 2013: Others, bound <60 million
      - July 2013: Terence Tao & Polymath project: bound 4680
      - Now: James Maynard, bound 600
      - Twin conjencture: still unproven, bound 2

      So the "big" discovery was Zhang, for managing to put a bound on it in the first place. The rest are improvements on that proof, but not very fundamental ones. Proving the twin conjencture would be huge, but nobody's done that yet. The Polymath project and probably many others are working on it. The conjencture is almost certainly true, but notoriously hard to prove. Probably the easiest "feel" to get for it is the Sieve of Eratosthenes, make a long list of odd numbers then strike out the multiples of primes. Once you strike out the 3s it'll be obvious you don't get triplets since 3, 9, 15, 21, 27 and so on are all multiples of 3 so the "candidates" are (5,7) (11,13), (17,19), (23,25) and so on. As you add more primes like 25 = 5*5 it'll get fewer and fewer pairs but they keep occuring rather randomly. It feels like that with infinite primes they'll randomly end up being next to each other an infinite number of times, but proving it is another matter. For example if you take the Fibonacci sequence (1,1,2,3,5,8,13,21...) it's obvious it's an infinite series but the distance between numbers also grows to infinity. Not so with primes, by these proofs.

      --
      Live today, because you never know what tomorrow brings
    6. Re:Summary by gnasher719 · · Score: 4, Insightful

      So in summary, if a pair of primes is defined by one following the other, it was theorized that we would find an infinite number of such pairs separated by 2. Various people have proven that gap to be from 70m, 60m, 4680, and now 600. Thank you James Maynard.

      Here's what it real means: There were conjectures, one of them famous, which stated:

      There are infinitely many pairs (p, p+2) of consecutive primes.
      There are infinitely many pairs (p, p+4) of consecutive primes.
      There are infinitely many pairs (p, p+6) of consecutive primes.
      ...
      There are infinitely many pairs (p, p+600) of consecutive primes.

      It is now proven that at least one of these conjectures is true.

    7. Re:Summary by Anonymous Coward · · Score: 0

      It was Yitang Zhang who settled the original long-standing open question - that being, is there any number such that you will always find pairs of primes separated by that number or less. The ultimate goal is to solve the twin prime conjecture - bringing the number in question down to 2.

      What's the problem? You can always find '3' and '5'. It's not like they hide or something.

    8. Re:Summary by readin · · Score: 1

      Explanation by car analogy:

      You're driving on a highway leaving a city. At every prime numbered mile marker there's a gas station. As you leave the city the gas stations are close together, with a station at the 2 mile marker, another at the 3 mile marker, another at the 5 mile marker, etc. As you get into the suburbs the gas stations are less frequent. As you get into the desert you find that gas stations are hard to find.

      But you notice something - it seems that no matter how far you drive into the desert, you occassionally find gas stations just two miles away from each other. You start calling these pairs "twins". Now someone has told you there are an infinite number of gas stations on the road, but you're wondering if there are an infinite number of twins. Will there always be more twins in front of you, or at some point will you have past the last pair? The Twin Primes Conjecture suggests there will always be another pair of twin gas stations on the road, but it has never been proven.

      Well, you think, so that's never been proven, but I've also noticed that sometimes I see gas stations just 4 miles apart. Does anyone know whether that will stop occurring? At some point will I pass the last pair of gas stations that are 4 miles apart? Again the answer is, nobody knows. How about 6? 8?

      Until recently, the answer was always, nobody knows. Then this Chinese guy proved that if you're looking for pairs of gas stations that are less than 70 million miles apart, there will always be such a pair on the road in front of you.
      Then somebody else proved that there would also always be a pair of gas stations in front of you less than 5000 miles apart. Most recently, someone proved that you would always have in front of you some pairs of gas stations that are within 600 miles of each other.

      We still suspect that will can always look forward to finding more twin gas stations, pairs that are within 2 miles of each other, but we don't have a proof yet.

      --
      I often don't like the choices people make, but I like the fact that people make choices. That's why I'm a conservative.
    9. Re:Summary by wonkey_monkey · · Score: 1

      What's the problem? You can always find '3' and '5'. It's not like they hide or something.

      The problem is you're not getting it. The unproved, but widely believed to be true, conjecture is: you will always be able to find, as you count higher and higher, more pairs of primes separated by 2.

      --
      systemd is Roko's Basilisk.
    10. Re:Summary by Anonymous Coward · · Score: 0

      I understood it slightly differently. The conjectures as I understood them are:

      There are infinitely many pairs of primes (p,p+k) with 2=k=2 (i.e. k=2).
      There are infinitely many pairs of primes (p,p+k) with 2=k=4.
      There are infinitely many pairs of primes (p,p+k) with 2=k=6. ...
      There are infinitely many pairs of primes (p,p+k) with 2=k=600.

      Note that each one is implied by the previous one. The first one is the twin prime hypothesis. The last one now has been proven true.

    11. Re:Summary by Anonymous Coward · · Score: 0

      600 is the lowest you can go because it's the gap between 81426773 and 81426173 (among others)

  13. momkind intends to keep us all on equal footing by Anonymous Coward · · Score: 0

    phony #'s be damnned

  14. our spiritual centerpeace gets uncounted again? by Anonymous Coward · · Score: 0

    billions of innocents (all of us unchosens) in the unbalance

  15. Twin primes ? by ctrl-alt-canc · · Score: 2

    They are not so sexy, after all...

    1. Re:Twin primes ? by ebno-10db · · Score: 1

      Only a mathematician would think that two primes separated by six is "sexy". And they say programmers and engineers are a sad lot.

    2. Re:Twin primes ? by Anonymous Coward · · Score: 0

      It's a play on words in Latin based on the prefix sex- meaning 6. You can go back to sleep now.

  16. Need a summary of the summary by Anonymous Coward · · Score: 0

    Ok, I'm dense.. I don't get it. What are they saying exactly?
    Are they saying we will always find a prime number within 600 of another prime number?
    If that were true, you'd think we'd have figured it out with the help of computers by now?
    I must be wrong in my understanding.

    1. Re:Need a summary of the summary by Anonymous Coward · · Score: 0

      Ok, I'm dense.. I don't get it. What are they saying exactly?
      Are they saying we will always find a prime number within 600 of another prime number?
      If that were true, you'd think we'd have figured it out with the help of computers by now?
      I must be wrong in my understanding.

      Your understanding is correct. And no, computers can't help because well prime numbers are infinite.
      At a certain your uber super quantum bio gel computer will run out of resources and you'll be none the wiser.

    2. Re:Need a summary of the summary by JTsyo · · Score: 2

      You will find 2 prime numbers within 600 of another prime pair.

    3. Re:Need a summary of the summary by ledow · · Score: 5, Informative

      That is, basically, the theory, yes. But if we can get that number down to "2" it proves a centuries-old conjecture that could lead to all sorts of interesting proofs of other things becoming true also.

      In terms of computers:

      You do realise that we use the difficulty of, in particular, finding large prime numbers as the basis for most modern security protocols implemented on computers? Precisely BECAUSE it's so hard to do?

      We're not talking about 2, 3, 5, 7, etc. but we're talking about primes with MILLIONS of digits. Primes so large that even to prove they are prime can take a long time. Primes so enormous that multiplying two of them together makes a number that's almost impossible to factorise back to the correct original primes, so much so that we use it as the basis for things like SSL, TLS, etc.?

      And, no, computers can't do mathematical proof. They can help as tools but they are dumb. You do not prove that every number to infinity has a prime within, say, 600 numbers by printing out every number. By definition you'll be there until infinity on even the fastest possible machine in the universe. You could prove that primes up to a number X that would hold true, but X would never be sufficient to prove it was always true. Just the fact that primes only have to be N numbers apart before you hit the next one could lead to mathematics that might well accelerate the discovery and manipulation of primes themselves.

      But if you come up with a clever mathematical proof that GUARANTEES the answer, no matter what X is or how many billions of digits it has, without having to worry about ever finding a *particular* prime, then you have something that a mathematician can take as "fact" and incorporate into larger proofs about the universe. Imagine if we just assumed that every prime was like this, and applied it to a large scale engineering project, and then found out that actually - once you get past a few billion atoms - the premise doesn't hold? It'd be catastrophic.

      The last "proof by computer" (i.e. by brute-force rather than as a tool) was the four-colour theorem. And even that was just because the problem could be reduced (by a mathematician, and using other proven theories, and logical inference) to a few thousand cases that the computer could iterate. It was used as a time-saver back in the days of manual calculation, not mathematical proof.

    4. Re:Need a summary of the summary by Anonymous Coward · · Score: 0

      > Ok, I'm dense..

      Prime numbers aren't dense in R. Proof is left as an excercise to the reader.

    5. Re:Need a summary of the summary by m2 · · Score: 1

      No, they are saying that you can always find a pair of primes separated by 600. Let's say you list all the primers between 2 and N. You enumerate all the pairs whose difference is 600. What they are saying is that if you look beyond N, you will always find another such pair. They are NOT saying how much further you have to look.

      They are *not* saying that given any prime number p, then p+600 is also prime.

      Their goal is to demonstrate that the same is true for 2 instead of 600.

    6. Re:Need a summary of the summary by smallfries · · Score: 4, Informative

      No we don't.

      Primality testing is easy - the problem is in P. Approximate methods for finding primes are very efficient. Exact checking is rarely used.

      Modern security protocols rely on the problem of factoring a number into primes being difficult. Or on inverting exponentiation within a prime field.

      --
      Slashdot: where don knuth is an idiot because he cant grasp the awesome power of php
    7. Re:Need a summary of the summary by x_IamSpartacus_x · · Score: 5, Informative

      It looks like you don't understand what GP was asking (at best) or you don't understand the summary/primes.
      I think the GP was asking if there are always less than 600 between primes. The answer to his question is "no". The higher you go the larger gaps can be between primes. There can be untold millions/billions/trillions etc. between two distinct primes. This proof shows not that there are never more than 600 between primes, but that there are an infinite number of pairs of primes that are separated by less than 600. The difference is small but important. There may be two primes separated by a vast number, yet the higher you go there will always be a pair of primes coming up that are separated by less than 600.

      For example:

      The numbers
      2^57,885,161 - 1
      and
      2^43,112,609 - 1
      are primes. They have 17,425,170 and 12,978,189 digits in them. They are the largest two primes we know of. They are separated by a bunch of numbers in between them, almost 5,000,000 DIGITS (note digits not numbers) and all the numbers between them are composites. HOWEVER, the next largest prime may simply be (2^57,885,161 1) + 600 because there will always be a chance that there is a prime coming up less than 600 away from the current highest prime.

      This is getting closer and closer to proving the long held belief/hope that there are an infinite number of primes separated by only 2. NOT that EVERY prime is separated by 2 from every other prime. That would be obviously false. Simply that there are an infinite number of primes salted throughout all those impossibly high ones that are only 2 apart.

    8. Re:Need a summary of the summary by Kjella · · Score: 3, Informative

      No, the maximum distance grows without bounds. What this proves is that you can always find two more primes that are less than 600 apart, so the minimum distance does not grow without bounds. It has absolutely nothing to do with the distance between one pair of primes and another pair.

      --
      Live today, because you never know what tomorrow brings
    9. Re:Need a summary of the summary by Warbothong · · Score: 5, Informative

      And, no, computers can't do mathematical proof. They can help as tools but they are dumb. You do not prove that every number to infinity has a prime within, say, 600 numbers by printing out every number. By definition you'll be there until infinity on even the fastest possible machine in the universe. You could prove that primes up to a number X that would hold true, but X would never be sufficient to prove it was always true. Just the fact that primes only have to be N numbers apart before you hit the next one could lead to mathematics that might well accelerate the discovery and manipulation of primes themselves.

      But if you come up with a clever mathematical proof that GUARANTEES the answer, no matter what X is or how many billions of digits it has, without having to worry about ever finding a *particular* prime, then you have something that a mathematician can take as "fact" and incorporate into larger proofs about the universe. Imagine if we just assumed that every prime was like this, and applied it to a large scale engineering project, and then found out that actually - once you get past a few billion atoms - the premise doesn't hold? It'd be catastrophic.

      What you say has nothing to do with computers. Why would anyone program a computer to work case-by-case like that? It's just as futile as going case-by-case by hand. Likewise, if one is inclined to generate higher-level, logical proofs by hand, then why not program a computer to generate higher-level, logical proofs? Oh wait, that's been done for decades (eg. AUTOMATH, or the entire field of Automated Theorem Proving).

      The last "proof by computer" (i.e. by brute-force rather than as a tool) was the four-colour theorem. And even that was just because the problem could be reduced (by a mathematician, and using other proven theories, and logical inference) to a few thousand cases that the computer could iterate. It was used as a time-saver back in the days of manual calculation, not mathematical proof.

      Erm, what lets you define "proof by computer" as "by brute-force"? Are you claiming that all computer programs are brute-force? That's clearly nonsense. Are you claiming that a computer running an efficient algorithm is just a 'tool' and that the Mathematical ability actually exists in the algorithm's programmer? If so, you must also claim that Deep Blue's programmers are much better chess players than Deep Blue. In that case, why weren't they the world champions?

      Also, the brute-force 'proof' of the Four Color Theorem, from 1976, was unsatisfactory to many people. It only proved the Four Color Theorem under the assumption that the program is correct, but nobody could verify such an assumption. In 2005 a new proof-by-program was constructed, but this time the program was written and verified in Coq. Only a tiny bit of code needs to be verfied in order to trust this proof (Coq's implementation of the Calculus of Inductive Constructions), and since this code is shared by all Coq users it's already had many eyes on it since appearing in the mid 1980s.

    10. Re:Need a summary of the summary by Zalbik · · Score: 1

      No, that's not the theory at all....

      The theory is that no matter how high you look, you can always find 2 prime numbers within 600 of each other.

      i.e. For any number X, there exists a pair of prime numbers Y, Z where Z>X and Y>X and Z-Y600

      It's entirely possible that having found Y,Z, there are no other primes anywhere near those two.

    11. Re:Need a summary of the summary by Anonymous Coward · · Score: 1

      You do realise that we use the difficulty of, in particular, finding large prime numbers as the basis for most modern security protocols implemented on computers? Precisely BECAUSE it's so hard to do?

      We're not talking about 2, 3, 5, 7, etc. but we're talking about primes with MILLIONS of digits. Primes so large that even to prove they are prime can take a long time.

      That's not how public-key crypto works at all.

      Generating large primes is dead easy. This is exactly what Java keytool and OpenSSL to every time you ask them to generate a private key: they generate two large prime numbers (hundreds of digits each, not millions) and the private key is those two numbers, while the public key is the product of those two numbers. What makes this kind of crypto hard to crack is the difficulty of factoring the product of two large primes: the search space is absolutely humongous. Determining whether a given number is prime or not is much easier.

    12. Re:Need a summary of the summary by gnasher719 · · Score: 1

      Their goal is to demonstrate that the same is true for 2 instead of 600.

      The _real_ hypothesis is this: Given _any_ pattern, like (p, p+2, p+6, p+8) where it isn't obvious that only a finite number of solutions exist, there will be an infinite number of primes following that pattern.

      A case where there is obviously a finite number of solutions is (p, p+4, p+8) because one of the three numbers must be divisible by 3. Or any pattern involving an odd number like (p, p + 1027); either p or p + 1027 must be even so except for p = 2 they can't be both primes.

    13. Re:Need a summary of the summary by gnasher719 · · Score: 1

      No, the maximum distance grows without bounds. What this proves is that you can always find two more primes that are less than 600 apart, so the minimum distance does not grow without bounds. It has absolutely nothing to do with the distance between one pair of primes and another pair.

      A simple proof: If you take a large number n, then n! + 2 is divisible by 2, n! + 3 is divisible by 3, and so on until n! + n which is divisible by n. n! + 1 and n! + n + 1 might be primes, but none of the numbers in between. So we have a gap between prime numbers of at least n.

    14. Re:Need a summary of the summary by Anonymous Coward · · Score: 0

      Four Color Theorem's tricky. The high-school definition has a known counterexample requiring only 5 regions. The college level definition excludes the nonsense that the counterexample uses.

    15. Re:Need a summary of the summary by Zalbik · · Score: 4, Informative

      That is, basically, the theory, yes

      No, that's not the theory at all. The theory does not say there is always a prime within 600 of another (that's simply not true).

      The theory says for any number X, there is a pair of primes larger than X within 600 of each other. That pair may be 2 larger than X, 12 larger than X, or 21,515,359 larger than X.

      Everything else you said is pretty much spot on though.

    16. Re:Need a summary of the summary by Zalbik · · Score: 1

      No.
      What this theory says is that no matter how far up you look on the number scale, you can always find a pair of larger primes that are separated by less than 600.
      i.e. for any number X you always find primes larger than X that are closer than 600 from each other

      In the opposite direction (what is the maximum gap between primes), the gap increases without bound.
      i.e
      For any number X you can always find closest primes that are more than X apart.

      Here's a proof:
      Take any number N
      N! = (N) x (N-1) x (N-2) x...x (3) x (2) x(1) (i.e. N times itself minus 1 times itself minus 2, etc....the factorial of N)
      N! is not prime...it is divisible by all numbers from 1 to N by definition.
      N!+2 is not prime...it's divisible by 2 (remember N is divisible by 2 and 2 is divisible by 2)
      N!+3 is not prime...it's divisible by 3
      .
      .
      .
      N!+N is not prime...it's divisible by N.

      That means none of the numbers between N!+2 and N!+N are prime, so we have a gap of at least N-2.

      This is true for ANY number N, so we can always find a gap as large as we want.

    17. Re:Need a summary of the summary by ChrisTaylor2904 · · Score: 1
      There exists an infinite sequence of primes p_n for which there is another prime somewhere in the range between p_n + 2 and p_n + 600.

      It isn't trying to cover every prime, just saying that no matter how far you go along them, you'll always be able to find another "nearby pair" further on.

      The holy grail of the exercise is to bring the 600 down to 2, so that we'll be able to say there are an infinite number of so-called twin primes.

    18. Re:Need a summary of the summary by ChrisTaylor2904 · · Score: 1
      Bad form to reply to myself, sorry, but another way to think of it is to look at the differences between consecutive primes.

      Say d(n) = p(n+1) - p(n).

      Write down d(n) as a list of numbers.

      It'll bounce around all the time (see other posts for proof that you can always find a value as large as you like), but you'll also always be able to find a value that's 600 or less, and at that point you've found a "nearby pair."

      The holy grail of the full twin prime conjecture is just saying that there are an infinite number of 2s in the sequence of d(n)s.

    19. Re:Need a summary of the summary by Anonymous Coward · · Score: 4, Informative

      all the numbers between them are composites.

      Ahem. Those are the two largest known primes (because primes of that form are particularly easy to search for using existing techniques), but there's nothing to say that there are not unknown primes between them. In fact, there almost certainly are many; the density of primes in that region should be on the order of 1 in every 100 million integers, so there are probably at least about 10^17425161 other primes in that span.

    20. Re:Need a summary of the summary by Anonymous Coward · · Score: 0

      OMG, I actually understood that. Thanks!

    21. Re: Need a summary of the summary by Anonymous Coward · · Score: 0

      This is also wrong. You will find an unlimited Number of Primes 600 apart. This is Not true for an arbitrary X

    22. Re:Need a summary of the summary by Anonymous Coward · · Score: 0

      Thank you for that :)

    23. Re:Need a summary of the summary by Anonymous Coward · · Score: 1

      For example:

      The numbers

      2^57,885,161 - 1

      and

      2^43,112,609 - 1

      are primes. They have 17,425,170 and 12,978,189 digits in them. They are the largest two primes we know of. They are separated by a bunch of numbers in between them, almost 5,000,000 DIGITS (note digits not numbers) and all the numbers between them are composites.

      Wrong.
      There are for sure a lot of prime numbers between 2^43,112,609 - 1 and 2^57,885,161 - 1. We don't know about any specific, but there exists theorem stating that there is always prime between x and 2x, where x is positive integer. So there is always a prime between 2^i and 2^(i+1). So there are at least
      57885161-43112609=14772552 (+-1) primes in this range.

    24. Re: Need a summary of the summary by Anonymous Coward · · Score: 0

      Saying you will find an unlimited numbers of primes pairs closer than 600 apart is the same thing as saying you can pick an arbitrary X, and fine two primes somewhere larger than X that form such a pair. Since there are only a finite many numbers below some arbitrary X, it is impossible for you to have unlimited natural numbers with any property without finding some above that X.

    25. Re:Need a summary of the summary by readin · · Score: 1

      Explanation by car analogy:

      You're driving on a highway leaving a city. At every prime numbered mile marker there's a gas station. As you leave the city the gas stations are close together, with a station at the 2 mile marker, another at the 3 mile marker, another at the 5 mile marker, etc. As you get into the suburbs the gas stations are less frequent. As you get into the desert you find that gas stations are hard to find.

      But you notice something - it seems that no matter how far you drive into the desert, you occassionally find gas stations just two miles away from each other. You start calling these pairs "twins". Now someone has told you there are an infinite number of gas stations on the road, but you're wondering if there are an infinite number of twins. Will there always be more twins in front of you, or at some point will you have past the last pair? The Twin Primes Conjecture suggests there will always be another pair of twin gas stations on the road, but it has never been proven.

      Well, you think, so that's never been proven, but I've also noticed that sometimes I see gas stations just 4 miles apart. Does anyone know whether that will stop occurring? At some point will I pass the last pair of gas stations that are 4 miles apart? Again the answer is, nobody knows. How about 6? 8?

      Until recently, the answer was always, nobody knows. Then this Chinese guy proved that if you're looking for pairs of gas stations that are less than 70 million miles apart, there will always be such a pair on the road in front of you.
      Then somebody else proved that there would also always be a pair of gas stations in front of you less than 5000 miles apart. Most recently, someone proved that you would always have in front of you some pairs of gas stations that are within 600 miles of each other.

      We still suspect that will can always look forward to finding more twin gas stations, pairs that are within 2 miles of each other, but we don't have a proof yet.

      --
      I often don't like the choices people make, but I like the fact that people make choices. That's why I'm a conservative.
    26. Re:Need a summary of the summary by Roachie · · Score: 1

      Suppose that the set of primes P is dense in R. Then for all x,y in R there exists a p in P such that x p y. Let x=0 and y=1, observe that there is no prime number greater then zero and less than one, contradiction. Therefore P is not dense in R.

      --
      This sig is not paradoxical or ironic.
    27. Re:Need a summary of the summary by Anonymous Coward · · Score: 0

      What on Earth are you talking about? There are entire software proof systems in existence, and they prove theorems every day. Not earth-shattering new mathematics like this, but useful theorems none-the-less (to make sure your large scale engineering project doesn't fall apart). "Proving" something using software includes brute-force testing, if you have a finite set to deal with, but it also includes all the other methods of proof - induction, reductio ad absurdum, et al.

    28. Re:Need a summary of the summary by Anonymous Coward · · Score: 0

      0 vs 10^17425161, now you're just picking hairs.

    29. Re: Need a summary of the summary by Anonymous Coward · · Score: 0

      There should be a -5 "I understand nothing about the matter at hand but I will explain to others why they're wrong" mod. If there is an infinite number of pair of primes 600 apart, then the possible number of pair of primes 600 apart, with one of the prime less than X, is finite. So there must be at least one pair of primes, both above X, less than 600 apart. The converse is also true.

    30. Re:Need a summary of the summary by Argilo · · Score: 1

      In fact, thanks to Bertrand's Postulate, we can be certain there are millions of primes between those two.

    31. Re:Need a summary of the summary by BrianJohns · · Score: 1

      And, no, computers can't do mathematical proof. They can help as tools but they are dumb. You do not prove that every number to infinity has a prime within, say, 600 numbers by printing out every number. By definition you'll be there until infinity on even the fastest possible machine in the universe. You could prove that primes up to a number X that would hold true, but X would never be sufficient to prove it was always true. Just the fact that primes only have to be N numbers apart before you hit the next one could lead to mathematics that might well accelerate the discovery and manipulation of primes themselves.

      But if you come up with a clever mathematical proof that GUARANTEES the answer, no matter what X is or how many billions of digits it has, without having to worry about ever finding a *particular* prime, then you have something that a mathematician can take as "fact" and incorporate into larger proofs about the universe. Imagine if we just assumed that every prime was like this, and applied it to a large scale engineering project, and then found out that actually - once you get past a few billion atoms - the premise doesn't hold? It'd be catastrophic.

      What you say has nothing to do with computers. Why would anyone program a computer to work case-by-case like that? It's just as futile as going case-by-case by hand. Likewise, if one is inclined to generate higher-level, logical proofs by hand, then why not program a computer to generate higher-level, logical proofs? Oh wait, that's been done for decades (eg. AUTOMATH, or the entire field of Automated Theorem Proving).

      The last "proof by computer" (i.e. by brute-force rather than as a tool) was the four-colour theorem. And even that was just because the problem could be reduced (by a mathematician, and using other proven theories, and logical inference) to a few thousand cases that the computer could iterate. It was used as a time-saver back in the days of manual calculation, not mathematical proof.

      Erm, what lets you define "proof by computer" as "by brute-force"? Are you claiming that all computer programs are brute-force? That's clearly nonsense. Are you claiming that a computer running an efficient algorithm is just a 'tool' and that the Mathematical ability actually exists in the algorithm's programmer? If so, you must also claim that Deep Blue's programmers are much better chess players than Deep Blue. In that case, why weren't they the world champions?

      Also, the brute-force 'proof' of the Four Color Theorem, from 1976, was unsatisfactory to many people. It only proved the Four Color Theorem under the assumption that the program is correct, but nobody could verify such an assumption. In 2005 a new proof-by-program was constructed, but this time the program was written and verified in Coq. Only a tiny bit of code needs to be verfied in order to trust this proof (Coq's implementation of the Calculus of Inductive Constructions), and since this code is shared by all Coq users it's already had many eyes on it since appearing in the mid 1980s.

      Very true in the sense that a programmer (and mathematician) that might not be good at solving certain complex problems that requires lots of short term memory with frequent storage and retrieval all within a finite time, can figure out a way to solve the problem of solving that problem.

  17. Closing the age gap: A good companion article by Anonymous Coward · · Score: 0

    http://www.scmp.com/lifestyle/technology/article/1256542/zhang-yitang-proof-mathematicians-life-begins-40

    Maybe a bit of a feel good article, but I think some deep questions are better answered by more seasoned (and likely more stubborn) mathematicians.

  18. James Maynard 'Keenan' by Anonymous Coward · · Score: 0

    This post reminded me of the singer of the band named Tool and the song Lateralus which uses Fibonacci sequence.

    http://www.youtube.com/watch?v=wS7CZIJVxFY

  19. What is the greatest lower bound? by Anonymous Coward · · Score: 0

    The result is astonishing. Does anyone happen to know what the greatest known lower bound is? (i.e. the largest known difference of two successive primes?)
    The prospect that one might eventually show the exact upper bound is even more astonishing.

    1. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 2, Informative

      There's none. the number of primes smaller than n is équivalent to n/ln(n) when n goes to infinity (thanks to Hadamard and Vallee Poussin theorem). If there was a upper bound for two successive primes, it wouldn't be the case.

    2. Re:What is the greatest lower bound? by ShanghaiBill · · Score: 5, Informative

      Does anyone happen to know what the greatest known lower bound is? (i.e. the largest known difference of two successive primes?)

      There is none.

      Proof: Select an arbitrarily large number N. The numbers between (N! + 2) and (N! + N) are all composite ((N! +2) is divisible by 2, (N! + 3) is divisible by 3, ..., and (N! + N) is divisible by N). Since you can find an arbitrarily large span of composite numbers, there is no upper bound on the gaps between primes.

      QED.

    3. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 2, Funny

      I call BS. That gap is only N-2.

    4. Re:What is the greatest lower bound? by SleazyRidr · · Score: 1

      It's people like you who make me want to learn more about maths. I felt like there could be an arbitrarily large gap between primes, but I had no idea how to express it. What you wrote, in addition that there are infinitely many primes proves the point perfectly.

    5. Re:What is the greatest lower bound? by ImprovOmega · · Score: 1

      The induction step and base case are obvious. The proof as laid out is correct for an arbitrary N. The induction step is to show that it is also true for N+1. Then your base case is to show that it is true for a specific N and N+1 like N=3 and N=4 (trivial to verify). At that point it is proven for all N where N is in the set of Natural Numbers and N >=3.

      Honestly I thought it was a very well formed comment for Slashdot. You shouldn't flame something just because you don't understand it. And if you are looking for strong rigor, this is Slashdot, not a mathematical journal. Anybody with 2+ years of undergrad college math should have been able to complete the proof without even hitting up a Google search.

    6. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 1

      Only N-2... for arbitrary N. Pick your claimed bound as (natural number) x. I will choose N = x + 4 (I'll not only hit your bound, but do better). Then there is a gap of length x+2, which is bigger than what you claimed is possible.

      Enjoy the troll feed.

    7. Re:What is the greatest lower bound? by ewibble · · Score: 4, Informative

      This is not a proof by induction it is a proof by contradiction, no induction step is needed.

      It assumes there is a number N such that their must be at 2 primes between M and M + N, for any M, then the proof goes on to show how to pick a M for which this is not the case.

      unless you are referring to the proof that the numbers between N! and N! + N are divisible not primes (clearly they are since you can write it as a*k+k = a*(N + 1) where a*k=N! for all values of k between 1 and N ). But you don't need induction to prove that either.

    8. Re:What is the greatest lower bound? by ImprovOmega · · Score: 1

      Contradiction works too. I just always found induction to be more intuitive personally. Honestly any proof technique that can be applied to a given problem (and it is often the case that more than one technique is easily used to prove a give problem) still results in a mathematically valid proof. I reworded it into a proof by induction because that makes sense to me and I was just filling in some minor blanks. A proof by contradiction would work too, but it just isn't my style.

    9. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      Um, this doesn't work...Not really useful though, as N! grows really fast compared to N.

      What do you mean it doesn't work and that it is not useful due to how fast N! grows? Do you think the integers stop when they get really big? The point wasn't to find a particular sequence of numbers that contain no primes. The point was to say that such a sequence exists for any N you can name, therefor one can't give a maximum prime number gap as there is always a bigger one for any sized gap you can name.

    10. Re:What is the greatest lower bound? by camperdave · · Score: 5, Funny

      Does anyone happen to know what the greatest known lower bound is? (i.e. the largest known difference of two successive primes?)

      There is none.

      Proof: Select an arbitrarily large number N. The numbers between (N! + 2) and (N! + N) are all composite ((N! +2) is divisible by 2, (N! + 3) is divisible by 3, ..., and (N! + N) is divisible by N). Since you can find an arbitrarily large span of composite numbers, there is no upper bound on the gaps between primes.

      QED.

      Wrong set. You're dealing with ALL primes. The question is about the set of KNOWN primes (you know, the ones listed in the NSA's Big Book of Primes). Between the known primes, there is a greatest known lower bound.

      --
      When our name is on the back of your car, we're behind you all the way!
    11. Re:What is the greatest lower bound? by mikael · · Score: 1

      Theoretically, it can't be any lower than 2. The fascinating thing is that as prime numbers become larger, they are found further and further apart, which plotted as a graph is more like a log n curve. But every now and again, you find a couple that are just two units apart. Usually one of them is something like (2^n)-1 and the other is (2^n)+1 . If the first one is written out as binary, it would form a prime number of 1's eg. 31. The only way such a binary number could have factors is one with 2^(n-1) number and the other being an odd number with 1 spaces a prime number distance apart.

      Simplest example would be 3 and 5. 3 = (2^2)-1, and 5 = (2^2)+1

      --
      Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
    12. Re:What is the greatest lower bound? by Flere+Imsaho · · Score: 1

      I understood some of those words.

      --
      It gripped her hand gently. 'Regret is for humans,' it said.
    13. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      N=2
      (2*1)+3=5 is not divisible by 3.

      QED you are a moron. Not to mention the article expressly states that real mathematicians (i.e. people working on math, not writing on /.) have proven there is an upper bound and it can't exceed 5,000.

      How this got voted informative at all is ridiculous.

    14. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      Your last statement is contradicting what even the summary covers. What James Maynard has shown is, if you give me an arbitrary number N, I will be able to find a pair of primes X and Y such that X > N and Y > N and ||X - Y||

    15. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      I don't think that's quite right. If there's an upper bound for distances between twin primes, then it stands to reason that it stands to reasons that the distance for single primes must be equal to (or less than) single primes.

      That proof does show there's an infinite number of primes, but that's a different question.

    16. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      Should read " If there's an upper bound for distances between twin primes, then it stands to reason that the distance for single primes must be equal to (or less than) twin primes."

    17. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      If there is an upper bound, then there is a greatest upper bound. QED, pal. Check and Mate!

    18. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      Yes, the summary says given any N, you could find an X and Y larger than N such that |X-Y| is less than 600. That doesn't contradict the post you are replying to at all, which says given any N, you can find primes W and Z such that |W-Z| is greater than N and there are no primes in between them. There is no contradiction here, as the first one doesn't say you will find that X and Y in a specific range, hence it doesn't say there needs to be primes separated by 600 between W and Z. That pair could be larger than W and Z.

    19. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      N=2
      (2! + 2) = x = (2! + 2)
      ((2*1) + 2) = x = ((2*1) + 2)
      (2 + 2) = x = (2 + 2)
      4 = x = 4
      x = 4, if we restrict ourselves to Z. 4 is divisible by 2.

      So, you can't add 2+2?

      QED.

    20. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      Slashdot removed the "less-than" part of my "less-than-or-equal" signs. Close enough.

    21. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      The useful part of a sieve is not that it gives us statements about the natural numbers in general, but that it gives us specific large primes, or every prime in a given range. As n! grows much faster than n, this is generally not useful for computing very large primes or ranges of very large primes.

    22. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      Great for sieves, but that is irrelevant to the post the GP was replying to, which was a proof there is no upper bound on the gaps between prime numbers. It had nothing to do with finding new primes, it was exactly a "statement about the natural numbers in general." The usefulness of that might vary depending on who you ask, but don't tell someone their screw driver doesn't work because you tried to use it as a hammer.

    23. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      Whoosh

    24. Re:What is the greatest lower bound? by Anonymous Coward · · Score: 0

      5 is also NOT between (N! + 2) and (N! + N) since both are 4 for N = 2.

      QED is it you who are the moron. The post you responded to was modded informative because it is. Your post isn't.

    25. Re:What is the greatest lower bound? by Guignol · · Score: 1

      The proof as laid out is correct for an arbitrary N. The induction step is to show that it is also true for N+1

      Appart for the major woosh, as you didn't get the obvious joke "this holds for any N" -> "no !!! only for N-2" (and I'm not sure at this point that you will even get the hint)
      You seem to have a major problem understanding the induction process which you claim to be your prefered and most intuitive way of understanding mathematical proofs. (but since you're a nice person you still admit that your GP's post is good enough for slashdot standards (thank you very much for him/her and the rest of us))
      So "The proof as laid out is correct for an arbitrary N" as you said... Why in the world would you need to show that it is also true for N+1 ? N+1 *is* an arbitrary N
      Induction is about having specific working examples (not arbitrary !!!) and proving that from here the next candidates must also be valid.
      Also, induction is not just about having N and proving N+1, or I could 'prove' you many funny things (sometimes you need more than just one element to get the next and depend on several ones (P(0) and P(1) are true, thus P(2) (depending on the previous two) is true) :)

  20. Still not a strong result... by gnasher719 · · Score: 1

    If N is between 2 and 10^260, then the number of primes less than N is more than N / 600. So in that range the _average_ gap between consecutive primes is less than 600. For N = 10^20 it is actually quite rare that the gap between two consecutive primes is over 600.

    1. Re:Still not a strong result... by Anonymous Coward · · Score: 0

      Given that the ultimate goal is to look for an infinite number of prime twins, I don't think that anybody is interested in the *average* gap.

    2. Re:Still not a strong result... by Anonymous Coward · · Score: 0

      You do know that numbers don't stop at 10^260, right? Sorry if I just blew your mind.

    3. Re:Still not a strong result... by Andy_R · · Score: 0

      Well, the summary may be misleading, but it seem to say that a proof has been found that the gap between two consecutive primes is NEVER over 600.

      --
      A pizza of radius z and thickness a has a volume of pi z z a
    4. Re:Still not a strong result... by Algae_94 · · Score: 1

      no it doesn't. The proof states that for any integer N, there exists at least one pair of prime number greater than N that have a gap between them that is not more than 600. There is also very likely a pair of consecutive primes greater than N with a gap larger than 600.

  21. Mistake? by Anonymous Coward · · Score: 0

    FTFA:
    "and if we assume the Elliott-Halberstam conjecture, that liminfn(pn+1pn) is less than or equal to 12"

    But the gap between 113 and 127 is 14, so either the Elliott-Halberstam conjecture is wrong or the proof is dubious.

    1. Re:Mistake? by Anonymous Coward · · Score: 0

      You should learn what "liminf" means.

  22. Increasingly Rare by Anonymous Coward · · Score: 0

    So, if the prime numbers become increasingly rare as you get bigger, but never get further apart than 600, then that's a sort of interesting result for two reasons. The obvious one is that the distance between primes increases at a decreasing rate. The subtler one is that there is some magic number out that is the LEAST upper bound for this growth in distance (I sort of doubt 600 is the smallest such bound). Whatever that least upper bound is will have profound implications for the nature of the universe. If that number is a prime, is it some sort of super-prime that can be used to predict all the other primes? If that number is composite, what is special about its prime factors? Heck, that magic number might not even be an integer. It might be some sort of transcendental number like phi, e or pi. It would be really mind-blowing to know that while integers are the simplest kind of numbers that we know, they may not be the most fundamental. Euler's Identity [e^(i*pi)+1=0] has hinted at that for quite some time. We might have to rewrite the fundamental theorem of arithmetic.

  23. Prime. Now we know. by Anonymous Coward · · Score: 0

    Nice. How soon do I get my FTL flying car?

  24. Re:Single mom thanked Obama by I'm+New+Around+Here · · Score: 0

    http://www.conservativeintel.com/2013/11/19/single-mom-thanked-obama-for-her-169mo-insurance-then-discovered-it-will-actually-cost-her-621mo/

    "Jessica Sanford of Federal Way, Wash., a freelance court reporter. She isn’t just any enrollee. As it happens, President Obama once mentioned her by name. She was so thrilled at getting a “gold” level insurance plan for herself and her son for just $169 per month that she had written Obama to thank him. And then he read from her letter and gave her a name-check in his October 21 Rose Garden speech. ...
    Unfortunately, Washington State did finally got back to Sanford about her application. That $452 subsidy we said you’d get? That was a mistake. You actually get zero. So for that gold plan, instead of paying $169 per month, you’d pay $621 per month."

    Awww, poor little LIV.

    Suck it drones. You served up a shit sandwich, now take a big ass bite and enjoy!

    That has nothing to do with prime numbers, idiot.

    --
    If you think I voted for Trump because of this post, you're wrong. I voted for Dr. Jill Stein of the Green Party. Again.
  25. thanks, I needed that by museumpeace · · Score: 5, Interesting

    so little of what news is dragged before me these days does much to make me hopeful of humanity's prospects on this planet. This story is the rare exception. We could be a great species. We could solve what looked for centuries to be impossible problems. We could...

    Thanks /. This story was not in any of my regular channels today.

    --
    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.
    1. Re:thanks, I needed that by AttillaTheNun · · Score: 1

      True, stories like this, and those related to my crack-smoking mayor, give me a reason to get up each morning.

  26. Is it just me by bluegutang · · Score: 1

    or have quite a number of difficult and important theorems been proven in the last couple decades? Fermat's last theorem, the Poincare conjecture, now lots of progress on this conjecture? What have mathematicians been doing right recently?

  27. I see that James Maynard... by Anonymous Coward · · Score: 0

    Has no wiki entry or web page indicating how good he is.

    Does that mean that he's a foreigner and NOT AMERICAN?

  28. Only mathematicians... by lemon031 · · Score: 0

    Only mathematicians would prefer a closer thigh gap...
    ...oh, wait. Never mind.

  29. The 600 gap: Good news, everybody! by SlovakWakko · · Score: 1
    Good news, everybody! It's been now proven, that there's an infinite number of one-hundred-times sexier primes, so there's enough for all of you lonely geeks :)

    You've got to find them, though...

  30. don't get excited! by Anonymous Coward · · Score: 0

    all of these are NON-CONSTRUCTIVE proofs!

  31. Where do such large numbers come from? by AdamHaun · · Score: 2

    The linked abstracts are pretty vague. Are there any mathematicians here who can explain how (seemingly arbitrary) large numbers like 600 or 70 million come out of these proofs? People are saying they're all tweaks of the same basic method, so what is that basic method, exactly?

    --
    Visit the
  32. Bill Gates agrees by SpaceLifeForm · · Score: 1
    ``The obvious mathematical breakthrough would be development of an easy way to factor large prime numbers.'' -Bill Gates, The Road Ahead, pg. 265

    Perhaps, he was educated as to the stupidity of his remark later.

    --
    You are being MICROattacked, from various angles, in a SOFT manner.
  33. My modified Goldbach Conjecture by SpaceLifeForm · · Score: 1
    Excepting 33 small numbers, all even numbers can be represented as the sum of two odd primes, BOTH of which are members of a twin prime set. The 33 exceptions of course have solutions to the normal Goldbach Conjecture, it is just that one or both of the primes do not have a corresponding twin.

    Note if you can find the proof of this, then you have killed multiple birds with one stone.

    You get the infiinite twins problem solved.
    You get the Goldback conjecture solved.
    And you find that is also shows that there are infinite sets
    of twin primes separated by any distance.
    Which means there are infinite quad primes as I mentioned above.

    --
    You are being MICROattacked, from various angles, in a SOFT manner.
  34. Meetup by Anonymous Coward · · Score: 0

    Meetup is the world's largest network of local groups. Meetup makes it easy for anyone to organize a local group or find one of the thousands already meeting up face-to-face. More than 9,000 groups get together in local communities each day, each one with the goal of improving themselves or their communities.For more info , please visit http://www.meetup.com/

  35. Out of curiosity... by nctritech · · Score: 1

    ...does this affect encryption in some way? My understanding is that a lot of encryption relies on the difficulty of finding prime numbers. I may be wrong. (It's certainly not my specialty.)

  36. Wait a minute... by dave420 · · Score: 1

    Why isn't cold fjord in here blaming Snowden for all this?

  37. Some garret! by Anonymous Coward · · Score: 0

    Garret? I wouldn't exactly call Oxford's maths department a garret!

  38. What about distribution? by BrianJohns · · Score: 1

    What an amazing discovery! Is there a pattern to the distribution to such pairs of primes? Are they composed of compound sets or is their distribution entirely unpredictable? When people make such discoveries or proofs, we get the chance in our lifetime to pose the next round of questions, the ones that might take decades (or centuries) to answer. Great news item!