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Millennium Prize Awarded For Perelman's Poincaré Proof

epee1221 writes "The Clay Mathematics Institute has announced its acceptance of Dr. Grigori Perelman's proof of the Poincaré conjecture and awarded the first Millennium Prize. Poincaré questioned whether there exists a method for determining whether a three-dimensional manifold is a spherical: is there a 3-manifold not homologous to the 3-sphere in which any loop can be gradually shrunk to a single point? The Poincaré conjecture is that there is no such 3-manifold, i.e. any boundless 3-manifold in which the condition holds is homeomorphic to the 3-sphere. A sketch of the proof using language intended for the lay reader is available at Wikipedia."

117 comments

  1. I'm amazed. by Anonymous Coward · · Score: 0

    I was thinking about the same subject during American Idiot, err Idle, Idol.

    1. Re:I'm amazed. by PopeRatzo · · Score: 3, Funny

      Yeah, Perelman thinks he's so smart. Feh.

      Math ain't rocket science.

      --
      You are welcome on my lawn.
    2. Re:I'm amazed. by Puff_Of_Hot_Air · · Score: 2, Insightful

      Most rocket science isn't rocket science.

    3. Re:I'm amazed. by treeves · · Score: 1

      When I look at just the descriptions of this kind of math, I'd say "Rocket Science is easy. It isn't Math."

      --
      ...the future crusty old bastards are already drinking the Kool-Aid.
    4. Re:I'm amazed. by steelfood · · Score: 1

      It's engineering.

      --
      "If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be."
    5. Re:I'm amazed. by frieko · · Score: 1

      "You tell people I'm a ROCKET SCIENTIST?!!!" - Sheldon Cooper

    6. Re:I'm amazed. by Anonymous Coward · · Score: 0

      The "slashdot poincare conjecture solved" conjecture:
      "given that a russian solved the conjecture slashdot will eventually get soviet russia jokes"

        But all we got so far is this meager "rocket science" jokes thread.

      In soviet russia, prizes try to get YOU!

  2. Well, sure by BadAnalogyGuy · · Score: 2, Funny

    Look, if you're going to use Ricci Flow to complete the proof, we all might as well pack up and go home. It's like the cheat code for all these manifold questions.

    1. Re:Well, sure by Obyron · · Score: 2, Funny

      Look, if you're going to use the Quadratic Formula to complete the proof, we all might as well pack up and go home. It's like the cheat code for all these binomial questions

      --
      --Obyron
    2. Re:Well, sure by JoshuaZ · · Score: 2, Interesting

      Ricci flow is an incredibly clever and sophisticated set of techniques. It is a very difficult technique to use and is by no means a "cheat code" for manifold questions. Most obviously, Ricci flow has been used with success to answer some aspects of the geometrization conjecture http://en.wikipedia.org/wiki/Geometrization_conjecture but still leaves a lot. In order to have a truly good understanding of low-dimensional manifolds we are likely going to need some additional technique that has not yet been discovered.

  3. Re:what about... by MR.Mic · · Score: 4, Informative

    You can easily determine the cubic volume of a spherical cavity by using the formula: V = 4/3 PI R^3.

    However, in the case of your image, the volume would probably be better matched by a cylindrical volume: V = PI R^2 H

    On second thought, a one-sheet hyperboloid would probably be the best match.

  4. Some background by ThoughtMonster · · Score: 5, Informative

    For those just in, here's an article covering Perelman and his theorem.

    This wikipedia entry covers some controversies following the article.

    1. Re:Some background by _|()|\| · · Score: 2, Informative
      Some previous Slashdot coverage, since they don't show up as related stories:

      I also see a headline from June 2006, "Chinese Mathematicians Prove Poincare Conjecture," but the link is broken.

  5. Bread and Cheese by alewar · · Score: 2, Funny

    I hope Perelman will be able to afford better food than bread and cheese now.

    1. Re:Bread and Cheese by Anonymous Coward · · Score: 1, Funny

      I hope Perelman will be able to afford better food than bread and cheese now.

      Indeed. it's all "pain et fromage" from now on.

    2. Re:Bread and Cheese by shutdown+-p+now · · Score: 2, Funny

      Given his personality, I think he'll rather appreciate the fact that he can afford more bread and cheese now.

    3. Re:Bread and Cheese by Anonymous Coward · · Score: 0

      or... Better bread and cheese!

    4. Re:Bread and Cheese by Anonymous Coward · · Score: 0

      I hope Perelman will be able to afford better food than bread and cheese now.

      I think he is more into mushrooms, actually.

  6. Millennium Prize? by Anonymous Coward · · Score: 0

    What Millennium are we talking about here? Its now 2010, 9 years after the start of the new Millennium.

    1. Re:Millennium Prize? by cc1984_ · · Score: 1

      What Millennium are we talking about here? Its now 2010, 9 years after the start of the new Millennium.

      Just in case that wasn't a joke:

      http://www.claymath.org/millennium/

      The challenge was set in 2000

  7. What does he win? by name_already_taken · · Score: 2, Informative

    Since neither the summary nor either article tell you what the guy wins, (almost like it's a secret), here's a wikipedia entry that does.

    It's a million dollars.

    --
    Putting moderation advice in your .sig lowers your karma!
    1. Re:What does he win? by PopeRatzo · · Score: 1

      It's a million dollars.

      So, I can't even say "If he's so smart, why ain't he rich"?

      Shit.

      --
      You are welcome on my lawn.
    2. Re:What does he win? by atomic777 · · Score: 3, Insightful

      It's amazing that TFA doesn't mention a thing about whether Perelman will actually accept the prize. What will happen to the prize money if he does not accept? The million dollars disappears into Lichtenstein numbered bank accounts 2718-282 and 3141-519?

    3. Re:What does he win? by L4t3r4lu5 · · Score: 1

      I was thinking one of two things here:

      - "How did you know my account numbers?"

      - "That's the same code I use on my luggage!"

      Please, delete as appropriate.

      --
      Finally had enough. Come see us over at https://soylentnews.org/
    4. Re:What does he win? by Anonymous Coward · · Score: 1, Funny

      that's the same code I use on my loggage

    5. Re:What does he win? by CityZen · · Score: 1

      These days, it seems you need a million dollars just to get by...

  8. Great news by Frans+Faase · · Score: 5, Informative

    I am very happy that they have awarded the price only to him, although he did meet the requirement that the proof should be published in a peer-reviewed journal. I am very happy that they did not included those two Chinese guys who did write down the proof (about 260 pages) and claimed that they had proven the conjecture. Perelman was very upset by this especially that other mathematics did not raise their voice. I hope that Perelman will accept the price. He said (some years ago) that he would only decide when the offer was made, if he would except the price or not.

    1. Re:Great news by Arthur+Grumbine · · Score: 1

      I am very happy that they have awarded the price only to him, although he did meet the requirement that the proof should be published in a peer-reviewed journal. I am very happy that they did not included those two Chinese guys who did write down the proof (about 260 pages) and claimed that they had proven the conjecture. Perelman was very upset by this especially that other mathematics did not raise their voice. I hope that Perelman will accept the price. He said (some years ago) that he would only decide when the offer was made, if he would except the price or not.

      So, you're saying that for Perelman, The Prize is Right?

      --
      Now that I think about it, I'm pretty sure everything I just said is completely wrong.
    2. Re:Great news by Anonymous Coward · · Score: 0

      Accept. Just saying.

  9. What I would like to know is by Anonymous Coward · · Score: 0

    what was PRISM's contribution on the discovery.

    (obscure?)

    1. Re:What I would like to know is by happy_place · · Score: 1

      What was COBRA's contribution on the discovery? (And now you know, and knowing is half the battle.)

      --
      http://www.beanleafpress.com
  10. Whatever... by Bentov · · Score: 2, Interesting

    It's not like wants the money or anything. He should at least take it and form a scholarship in his name. Jeez, the man is like a ./er, he lives with his mother.

  11. So will he accept? by Puff_Of_Hot_Air · · Score: 5, Informative

    Perelman has famously turned down the fields medal and shunned the world since the whole Yau political saga. Will he take this prize? I hope that he will. I think that the whole Yau trying to take the credit for the proof issue, sullied the entire world for Perelman. Perhaps now that the honour is being fairly directed at him in response to his work, Perelman will be able to re-enter society and enjoy some of the fruits of his labour.

    1. Re:So will he accept? by Jeff+DeMaagd · · Score: 1

      Has anyone had a hard answer as to why he turned down the prizes and medals? The author of "Perfect Rigor" seemed to think that Perelman thought the Fields Medal was beneath him. I don't think hiding away from society did him any good, especially if he's expecting other people to defend him when he seems not willing to do so himself.

    2. Re:So will he accept? by Obyron · · Score: 5, Interesting

      I can't take credit for finding this. Another Slashdotter was kind enough to link it the last time Perelman came up, but I found this to be very enlightening and illustrative of Perelman's personality as well as the whole Yau controversy. It's an article from the New Yorker co-written by Sylvia Nasar, who wrote the biography of John Nash, A Beautiful Mind. It contains what was at the time the only interview with Grigori Perelman, but I'm not sure if that's still true.

      Annals of Mathematic: Manifold Destiny

      --
      --Obyron
    3. Re:So will he accept? by Vellmont · · Score: 4, Insightful


      Has anyone had a hard answer as to why he turned down the prizes and medals?

      What his friends have said is he believes actually proving it is reward enough. It's like being the first person to land on the moon, and someone gives you a "you landed on the moon" prize.

      Still, a million dollars is something that can give you a lot of freedom. Turning it down is something that he might regret later.

      --
      AccountKiller
    4. Re:So will he accept? by Anonymous Coward · · Score: 1, Insightful

      He does not want to be defended. As far as I read the controversy, he does not want to fight at all, because he (quite rightfully, imO) thinks that science should not be fought over.
      Criticism is useful. Politics (Yau, you asshole!) is not.

    5. Re:So will he accept? by Puff_Of_Hot_Air · · Score: 5, Insightful

      Perelman is not a normal guy (obvious I realize, but hear me out). People like to subscribe 'normal' motives for behaviour they see as abnormal. I think this is why the idea that the fields medal was rejected as 'beneath' him was put forward. Arrogance is simple to understand. But what did Perelman actually say? "[the prize] was completely irrelevant for me. Everybody understood that if the proof is correct then no other recognition is needed". What Perelman was looking for was recognition for solving the problem. This was more important than the fields medal! What he got instead, was Yau and his cohorts claiming to have "really solved it." In Perelman's mind, political play such as this has no place in mathematics! Worse, his peers were not standing up to a) condemn this behaviour, and b) defend his paper. I think an important missing piece was that Perelman had not been officially recognized as having solved the Poincare conjecture. Now that this had been rectified, perhaps the world will be in enough order for him to rejoin it.

    6. Re:So will he accept? by mapkinase · · Score: 1

      Obviously, the question will he or will not cannot be answered this minute.

      What could be answered is the question of what will be more surprising: if he will accept or if he will not.

      I personally think that him accepting it would be more surprising for me.

      --
      I do not believe in karma. "Funny"=-6. Do good and forbid evil. Yours, Oft-Offtopic Flamebaiting Troll.
    7. Re:So will he accept? by NeoSkandranon · · Score: 1

      To reject something like that, because you don't care or think it's pointless comes across a whole lot like arrogance, especially worded as he apparently did.

      Why not go along with it? There would be zero harm in graciously accepting it and presenting the viewpoint more tactfully.

      --
      If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)
    8. Re:So will he accept? by sirrunsalot · · Score: 1

      Isn't the moral that you can take credit for anything you like? How about, "Sure, the kind Slashdotter who found it contributed a good thirty or thirty-five percent, but bookmarking and linking to it accounts for at least the other seventy-five percent. It was no small task."

    9. Re:So will he accept? by HaeMaker · · Score: 2, Informative

      He is not a native speaker of English. He might have mistranslated his thoughts.

    10. Re:So will he accept? by NeoSkandranon · · Score: 1

      Was not aware of that nuance, thanks.

      --
      If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)
    11. Re:So will he accept? by Anonymous Coward · · Score: 0

      Because of a single word that most people these days find totally alien:

      Integrity

      It would have been a violation of his own moral integrity to accept all the flattery and fanboi-ism surrounding his proofs, especially when it was patently obvious that such fanboi-ism was hollow, and without substance(QED because of their lack of outrage over the Yau debacle.)

      Like Shakespeare said: Above all else, to thine own self be true.

      To Perelman, his integrity was of higher value than either the field medal, or any prize money associated with it.

      I applaud his choice. "Arrogance" had nothing to do with it. From what I can read of the man, Integrity and Modesty are his first and middle names.

      If it wouldn't be in bad taste, I would send him a letter, to let him know that I understand and approve of his choice.

    12. Re:So will he accept? by trurl7 · · Score: 1

      Why not go along with? How about "moral stance"? Or if that's too abstract, how about this: the man is a bona fides genius. If anyone's got the right to ignore fatuous platitudes, I think his intellectual accomplishment confers the privilege. The better question is this: why do you think everyone needs to conform to your notion of "graciousness"?

      Perhaps this was not your intent, but you come across as that annoying neighborhood old lady that wants to see to it that everyone "conform", and gossips behind your back when you don't. Such small-mindedness in this community is embarrassing. Yeah, yeah. I'm new here.

    13. Re:So will he accept? by NeoSkandranon · · Score: 1

      It would appear I need to read more in detail about the whole situation

      --
      If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)
    14. Re:So will he accept? by Obyron · · Score: 1

      If I were going to go full Yau, I would claim that I discovered this article on the New Yorker's website, and that I am incensed because it is clearly an idea that I came up with first, and if you don't believe me just ask all of my Chinese friends.

      --
      --Obyron
    15. Re:So will he accept? by sans17 · · Score: 1

      From what I have read around here he did not reject Fields Medal. Since they never formally offered it to him. Or did they?
      "We will give it to you if you take it" is just BS.
      One more point to Perelman.

    16. Re:So will he accept? by NeoSkandranon · · Score: 1

      Generally speaking I don't feel like anyone has a right to be insulting or belittling when it costs nothing to be otherwise; this was how the phrase in the OP's comment came across.

      THAT SAID, I've read up more about the whole situation and clearly didn't have much of a grasp of the background when I made the above comment, so forget I said anything.

      --
      If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)
    17. Re:So will he accept? by trurl7 · · Score: 1

      It's so very embarrassing when one goes for the throat, and realizes not only was it an overreaction, the throat belongs to a better man.

      I shouldn't have attacked like that. I apologize. Thank you for being so controlled in your response. I will debate better henceforth.

      (And I agree, generally it's not ok to be rude. I have a math background so this whole melodrama stirred some ugly feelings.)

    18. Re:So will he accept? by afree87 · · Score: 1

      Actually, I'd say it isn't even a linguistic but a cultural problem. The New Yorker employed a Russian guy to explain his reasoning; he is a sort of Russian hermit. Imagine if Tolstoy went up against a person like Yau. I think there would be mutual disgust and bad feeling towards the literary community at large. Such a thing probably happened here.

    19. Re:So will he accept? by Anonymous Coward · · Score: 0

      It contains what was at the time the only interview with Grigori Perelman, but I'm not sure if that's still true.

      No, he was also quoted giving a favourable review to "Dating for Engineers".

    20. Re:So will he accept? by sirrunsalot · · Score: 1

      I shouldn't have attacked like that. I apologize. Thank you for being so controlled in your response. I will debate better henceforth.

      Wow. Thanks, guys (or possibly girls [but who are we kidding?]). I don't mean that sarcastically. Every time I read a comment online, my faith in humanity dips a little lower, but I do appreciate the civilized discourse. It's just not very often someone's response to a counter-argument is, "Yeah, I guess you're right. Sorry." I guess Obama does it every now and then, but there's plenty of political posturing involved. I should probably pay less attention to politics. Maybe mathematics, too.

      In fact this whole situation makes me pretty sad. Mathematics by itself is such a beautiful thing, so it's too bad that the second it's comprehended by human minds it's subject to territorial disputes. I applaud people like Perelman who elevate the subject above opportunities for personal gain. I certainly don't think such things are better left undiscovered, but I only hope his turning down the prize—if that's what he should choose to do, and it sounds like he might—has a positive impact on people across all fields that encounter the story. I'm not in pure mathematics myself, but it makes me sad to see research so often used as a vehicle for personal gain rather than an end in itself.

    21. Re:So will he accept? by Anonymous Coward · · Score: 0

      It's a small point, but the word you need is "ascribe", not "subscribe". Given that the rest of your comment is written in clear English, I thought you might care for the small correction.

  12. English Please by AP31R0N · · Score: 3, Insightful

    Could someone give us non-math geeks an explaination of this that does not include the following words: manifold homologous homeomorphic?

    i'll read the wiki page too, but i'm hoping someone here will take a crack at explaining in it plain English.

    Also: What does this mean? What are the applications? Not that it has to have any to be interesting.

    --
    Utilizing the synergization of benchmark e-solutions to pre-workaround action items!
    1. Re:English Please by Anonymous Coward · · Score: 0

      Someone already has, and it was linked, so go read it.

    2. Re:English Please by Obyron · · Score: 0, Offtopic

      Maybe Read the last sentence of TFS?

      --
      --Obyron
    3. Re:English Please by selven · · Score: 3, Informative

      Manifold = a surface created by taking pieces of paper and warping them. For example, cylinder is a manifold since it can be formed by attaching the two opposite sides of the paper to each other. If you then attach the two circles at the ends of the cylinder, you get a torus (ie. donut).

      Homeomorphic = there's a continuous function mapping points from one object to the other. This means that if two points are close to each other in the first object, they will be close together when the homeomorphism (the function) is used to map the points onto the second object. A square and the surface of a sphere, for example, are not homeomorphic since the square has edges and the sphere doesn't, so the mapping function has to jump somewhere, making it not continuous. Generally, two shapes are homeomorphic if you can deform one into the other (see animation here)

      Homologous = I don't know how that word got in there. It's not in the Wikipedia article.
      Simply connected = Any line drawn on the manifold that starts and ends at the same point can be slowly shrunk down to one point without taking any part of it off the manifold. A torus is not simply connected, since you can draw a line going around the cylinder and there's no way to take it off.

      As for implications, as far as I can see, it just tells us that lots of things can be deformed into spheres and gives us a simple test for determining if something can.

    4. Re:English Please by pomakis · · Score: 4, Informative

      I think the question is easier to understand if you knock everything down a dimension, because then it can actually be visualized. Take the surface of any three-dimensional object that doesn't contain any holes (e.g., a cup, but NOT a coffee mug with a handle). Can the surface be stretched/distorted to be shaped into a sphere? The answer is fairly obviously yes. But is this also true for four-dimensional objects? Stop trying to visualize it; you can't. You have to rely on the math instead. But that, I believe, is the question.

    5. Re:English Please by AP31R0N · · Score: 2, Funny

      Maybe read the second sentence of my post? Or read the post at all before replying to it? Maybe use question marks to mark questions, not childish, unhelpful snark?

      --
      Utilizing the synergization of benchmark e-solutions to pre-workaround action items!
    6. Re:English Please by HeckRuler · · Score: 1

      Ok, that finally sunk in. Thank you.

      I read the summary and what little mathmatical legs I got were sweapt out from under me. I read "A sketch of the proof using language intended for the lay reader is available at Wikipedia." and my instant reaction was "oh thank you god!"
      But when I read the wiki over but couldn't get my head around a one-dimensional circle, and a two-dimensional sphere.
      Read some other slashdotters posts and and some other wiki pages, and while I know more about manifolds than I ever strictly wanted to, it wasn't until your post that I realized that the hell poincare was going on about.

      Now, uh... why should I care? Will this help with research into the 4-dimensional manifold that is space-time (as seen by Einstein, apparently) and get us closer to flying cars and personal jetpacks?

    7. Re:English Please by CODiNE · · Score: 1

      A square and the surface of a sphere, for example, are not homeomorphic since the square has edges and the sphere doesn't, so the mapping function has to jump somewhere, making it not continuous.

      Sounds a lot like a map using Mercator projection.

      --
      Cwm, fjord-bank glyphs vext quiz
    8. Re:English Please by Coryoth · · Score: 3, Interesting

      It's really all about classifying shapes. For two dimensional things this is pretty easy, at least as far as the topology goes: you need to know the curvature and "how many holes does it have" and that's it -- this is the whole topologist not knowing a coffee cup from a donut since they both have one hole and hence can be deformed one into the other (note that this is two dimensional because we are considering the 2-dimensional surface on the donut and coffee cup). In dimensions higher than two things start getting trickier because more bizarre configurations become possible. Perelman's work, which actually goes toward proving the rather more far reaching Geometrization Conjecture (due to Thurston), essentially lays out how you can classify all the different (from a topological point of view) shapes of things in three dimensions and higher.

      What are the implications? Well, one reasonable question is: what is the topology of the universe like; what shape is the universe? Since the universe is a three dimensional manifold that turns out to be tricky. Perelman's work lays out the groundwork to be able to answer such a question.

    9. Re:English Please by John+Hasler · · Score: 1

      > it just tells us that lots of things can be deformed into spheres and gives
      > us a simple test for determining if something can.

      3-spheres ("ordinary" spheres are 2-spheres). Equivalent results have existed for all other spheres for some time.

      --
      Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
    10. Re:English Please by darkmeridian · · Score: 1

      That is the problem that was solved. The crazy thing is that it was proven for all dimensions other than ours in 1982. It took that long to prove the conjecture for the three-dimensional world that we live in. That's wild, no?

      --
      A NYC lawyer blogs. http://www.chuangblog.com/
    11. Re:English Please by Anonymous Coward · · Score: 0

      Yes. No.

    12. Re:English Please by chhamilton · · Score: 3, Informative

      Not quite true... a 3-sphere is actually the *surface* of a 4-dimensional sphere. So, not exactly something that lives in our world. In topology, the dimensions refer to the dimensionality of the surface, and not the space the surface lives in (ie: a circle drawn on a piece of paper is a 1-sphere, but the surface it was drawn on is 2-dimensional).

    13. Re:English Please by AP31R0N · · Score: 1

      Mod up please!

      Thanks. Interesting stuff.

      --
      Utilizing the synergization of benchmark e-solutions to pre-workaround action items!
    14. Re:English Please by jank1887 · · Score: 1

      still waiting for the simple.wikipedia.org article to fill me in.

      http://simple.wikipedia.org/wiki/Solution_of_the_Poincar%C3%A9_conjecture

      "Wikipedia does not yet have an article with this name."

    15. Re:English Please by jank1887 · · Score: 1

      there is a Simple article about the problem, though:

      http://simple.wikipedia.org/wiki/Poincar%C3%A9_Conjecture

    16. Re:English Please by TeknoHog · · Score: 1

      Stop trying to visualize it; you can't.

      But some people can visualize such things, you insensitive 3-clod!

      Seriously though, mathematical proofs cannot rely on a human's ability to visualize. Even the version in our dimensionality must be proved by doing the math.

      --
      Escher was the first MC and Giger invented the HR department.
    17. Re:English Please by martin-boundary · · Score: 1

      No, the mercator projection doesn't show either the north or south poles. They are implied, ie you know where they are supposed to be, but they're not actually on the map. So the mercator projection doesn't map the full earth sphere, only the earth sphere with two poles missing, which is homeomorphic to a cylinder.

    18. Re:English Please by daver00 · · Score: 1

      Unfortunately, there is absolutely no way to describe this stuff in "human" terms, you really just have to get your head around the concepts and even then you are likely to have no idea what this stuff is on about. Mathematicians could spend their whole career not understanding this stuff, easily.

      I'll try as best I can, but I can barely get my head around the most basic concepts here, so here I go: In topology we don't care so much about what you normally think of as mathematics, topology I guess you could say is a study of bulk mathematical structure in some sense, highly abstracted notions of geometric structure in this case, but topology goes beyond geometry and it is wrong to think of it as simply the study of manifolds and such. A manifold, the kind they are talking about, is a 'locally smooth surface', that means if you have the surface of a 3d object and zoom into a point anywhere, the region around the point will eventually begin to look 'flat', this means if you move around on the 3d surface, you can move in 2 dimensions only and encounter nothing discontinuous about the surface. Of course this extends to higher dimensions too. If you think of a map of the earth as a flat 2d grid, then the sphere that is the earth is a 2-manifold. Here we have embedded a 2-dimensional plane into a 3-dimensional space. If you then think about the general plane and how it stretches out infinitely, we can actually 'compactify' that infinite plane into a finite manifold by 'mapping' each point on the plane onto a point on the surface of a sphere, we and add one single point we can call 'infinity' and the once infinite plane is now 'compact'. The infinite plane has now become finite (sort of) by embedding it into higher dimensions.

      In topology a homeomorphism between topological spaces (a manifold is a topological space) just means we can find a perfectly reversible function which maps every point from one to every point in the other exactly one way, it means the two spaces will have the same structure and all theorems proven for one are true for the other. This is where the famous saying "the coffee cup is no different to the donut" comes from. If two topological spaces are homeomorphic, we can find some function which morphs one into the other, and hence they are simply the same thing. In terms of manifolds this is like saying we can warp, bend, twist and pass the manifold through itself, but never fold or cut, until one matches the shape of the other. So a donut can be made into a coffee cup, but never a sphere.

      The Poincarre conjecture is a way of characterizing a 3-manifold as homeomorphic to the 3-sphere. So we have stepped up a dimension from the flat earth/spherical earth example above. Now our basic manifold is locally flat in 3 dimensions, so locally it might look like 3-dimensional space while it globally exists in 4-dimensional space. If you walked around on the surface of a 3-sphere, you could move in 3 directions. In the case of the 2-sphere, we can characterize homeomorphic manifolds by the fact that if you take any circle on the surface of a sphere, you can contract it down to a point on the surface. This is not true for donuts, as some circles cannot contract down to a point, hence the sphere is not homeomorphic to the donut. So we then have a simple way of describing which manifolds are homeomorphic to the 2-sphere. Poincarre conjectured that this was possible for the 3-sphere.

      The proof, I can give no insight on, and I imagine most of the worlds best mathematicians would struggle to follow it. It took years to verify this proof, years of work and teams of mathematicians.

      As for usefulness, you need to step out of the structured world of classical applied mathematics and think in abstract ways. At face value there is very little of anything useful about this proof, other than gaining deeper insight into the geometry of 4 dimensional space. Topology is used in spatial databasing, image processing, protein folding/knot theory, lots and lots of physics (string theory especially) and ma

    19. Re:English Please by Anonymous Coward · · Score: 0

      I'm sorry to be petty, but your explanations of those mathematical terms is slightly misleading.
      Manifold (technically a 2 dimensional manifold) - A shape that when you look at it really closely resembles a plane. For example a sphere, a doughnut, 2 spheres, a plane.

      Homeomorphisms must be continuous and have a continuous inverse (this is much stronger than just requiring continuity).

      Simply Connected spaces must be connected as well as allowing loops to contract. Connected meaning that you can't 'pull the space apart'. For example two disjoint spheres are not connected.

      Homology is a theory which makes it easier to tell if two spaces are not homeomorphic (I'm not going to attempt a explanation of homologous, try http://en.wikipedia.org/wiki/Homology_theory )

      Roughly speaking in topology, people like to classify 'up to homeomorphism', ie. to regard two spaces that are homeomorphic as being 'the same', so the conjecture tells us that if a space satisfies the right properties then it is 'the same as' a sphere.

    20. Re:English Please by exploder · · Score: 1

      Manifolds don't "live in" any space. Yes, a 3-sphere can be imbedded in R^4 (or R^5 or R^n for any n>3), but for its definition, the 3-sphere does not refer to any ambient space whatsoever. Our world might very well be a 3-sphere...if it were large enough, we'd never know the difference, just like the good old ant-on-a-basketball.

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    21. Re:English Please by exploder · · Score: 1

      First, visualize an n-sphere for n=2. Then let n go to infinity.

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  13. Re:what about... by L4t3r4lu5 · · Score: 1

    I'll never look at a diabolo the same way again.

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  14. Who the fuck cares? by malp · · Score: 2, Funny

    The /. eds could make this article 10x more relevant to most people by titling it 'Man wins million dollar mental masturbation prize' or by explaining the practical applications of this discovery. Instead the summary is a list of techno jargon that'd put Star Trek to shame with no mention of the $$ prize nor details of the winner. Who is this guy? Why did someone give him so much money for solving for x? Can I too win cash money for balls? If not, can I out source next year's winner to india and take a cut of the prize?

    Anyway, this article's a lot better:http://www.newscientist.com/blogs/culturelab/2009/11/grigori-perelman-the-genius-in-hiding.php

    1. Re:Who the fuck cares? by DamonHD · · Score: 1

      -5 narrow-minded sour grapes.

      OK you can behave this way, just so long as we're able to rudely dismiss as "balls" anything clever you ever do that is not immediately relevant to us. And your music collection and wardrobe and taste in partners too since we're on a roll.

      Rgds

      Damon

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    2. Re:Who the fuck cares? by not-my-real-name · · Score: 3, Informative

      Nerds care.

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    3. Re:Who the fuck cares? by pjt33 · · Score: 1

      What are "most people" doing on /.? The people who do care already know how much the CMI prizes are and who Perelman is.

    4. Re:Who the fuck cares? by mariuszbi · · Score: 2, Informative

      The prize is 1 million USD and Perelman is this guy in the picture http://englishrussia.com/index.php/2007/06/15/perelman-in-a-subway/

  15. Re:what about... by Anonymous Coward · · Score: 0

    "You can easily determine the cubic volume of a spherical cavity by using the formula: V = 4/3 PI R^3."

    Prove it.

  16. Re:Linux Windows by ArsenneLupin · · Score: 0, Offtopic

    Mod parent as Insightful!

  17. controversial "proof" by Anonymous Coward · · Score: 0

    Good to see the Perelman fanboys up so early in the morning.

    But there seems to be just as many credible sources that felt Perelman did not satisfy the test of rigor.
    I guess Clay math is free to do what they wish with their own money.

    1. Re:controversial "proof" by Ukab+the+Great · · Score: 3, Funny

      I find the concept of mathematicians having fanboys who flame each other over proofs to be disturbing.

    2. Re:controversial "proof" by Anonymous Coward · · Score: 0

      I find it less disturbing than fictional characters having fanboys who flame each other over hypothetical situations which haven't occurred even in the fiction from which the characters originate.

      (ie, 'who would win in a fight')

      At least this flamewar is over something that might really matter.

      As to immediate applications- am I incorrect that this would allow the derivation of a deformation between two solid 3D shapes in animation? As far as I know, that's not a well understood problem.

  18. Re:Layman's terms? by Mitchell314 · · Score: 1

    I tried to make a smartass remark, but apparently /. is not math symbol friendly to say in the least.

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  19. Re:what about... by fuego451 · · Score: 1

    Oh god! Is that you, Dr Lippmann? I haven't heard those two words in 45 years. I think it was integrated algebra and trig class.

  20. Re:I would now like him to demonstrate... by Anonymous Coward · · Score: 0

    About fifty cords a day, if you believe the internet oracle.

  21. Summary of the Poincare conjecture is inaccurate by TheEmptySet · · Score: 2, Informative
    As someone who's job involves research into geometry and topology, I would like to point out that the summary is wrong in a couple of places. The Poincare conjecture states (in simple terms) that:

    Any closed smooth three dimensional space ('manifold') without boundary where all loops can be contracted to a point is 'homeomorphic' (essentially the same as) the three dimensional sphere (that is, the unit sphere in 4 dimensions).

    The words "homologous" and "boundless" have little/nothing to do with it.

  22. Re:Summary of the Poincare conjecture is inaccurat by TheEmptySet · · Score: 1

    Excuse me for replying to my own post. I should also mention that Poincaré's conjecture was not about 'a method for determining whether a three-dimensional manifold is a spherical'. It is simply the question of whether there are non-spheres in 3d which have all loops contractible (for a more accurate description, see the parent). The question about methods/algorithms for determining whether or not something is a 3-sphere is in itself very interesting though.

  23. I'm guessing by malp · · Score: 1

    most people on /. have no clue what this sentence means: Poincaré questioned whether there exists a method for determining whether a three-dimensional manifold is a spherical: is there a 3-manifold not homologous to the 3-sphere in which any loop can be gradually shrunk to a single point? The Poincaré conjecture is that there is no such 3-manifold, i.e. any boundless 3-manifold in which the condition holds is homeomorphic to the 3-sphere.

  24. from a mathematician by l2718 · · Score: 3, Interesting

    It's easier to explain the two-dimensional version, that is the version about surfaces. A mathematical surface is a kind of quilt: it's what you get from stitching together patches, each of which looks like a small piece of the plane. Just like with the quilt, if you bend or deform the surface it still is the same surface. Surfaces are completely "floppy".

    Now, most real-life quilts are rectangular and have a boundary where they end, but you can also "close" the quilt by stitching the boundary back onto itself -- what you get is a "closed" surface. For example, you can stitch all the boundary together and get a sphere. Or you can stitch opposite sides together and get a "torus" -- the surface of a doughnut. You can also make more complicated quilts, which look like the joining of several doughnuts, i.e. a doughnut with several holes.

    Next, one way that the sphere and doughnut-surface differ is that the latter has a hole. The way we express this is by looping a closed piece of string along the surface. With the sphere you can always slide the piece of string off the surface (we say that the sphere is "simply connected"), but with the torus you can run a loop of string along it in such a way that no deformation will allow you to take it off (we say the doughnut is "multiply connected").

    Finally, the "2d Poincare conjecture" is the statement that the only simply connected closed 2d surface is the sphere. In other words, if you can't link a loop with your closed quilt then your quilt can be deformed to be a round sphere. A strong version of this was proved by Poincare, among others.

    Now for the real "Poincare Conjecture" that was proved by Perelman, replace "2d" by "3d", so the quilt comes from stitching little cubes instead of little squares. The "closed and simply connected" assumptions are the same, and the conclusion is that the quilt is, up to deformation, the 3d sphere. It's much harder to visualize since now the quilt may not fit into regular 3d space. For example, the 3d sphere is what you get by stitching the whole boundary of the 3d cube together into one point (recall how we got a 2d sphere!) -- which is not something that fits into ordinary 3d space.

    1. Re:from a mathematician by KingKiki217 · · Score: 1

      Is forming something like a Möbius strip or a Klein bottle allowed? Or am I thinking in a different direction? I know a Klein bottle has weird characteristics; is it considered closed or simply connected?

  25. Come again! by Kreeben · · Score: 1

    "...is there a 3-manifold not homologous to the 3-sphere in which any loop can be gradually shrunk to a single point?"
    There's that whoosing sound again. I hear it once in a while.

  26. Re:what about... by CityZen · · Score: 2, Funny

    Well, I think the real question in this case should be what is the topology of the shape in question (the human body)? Isn't the so-called "cavity" really just a long tube connecting two openings to the outer surface? If that be the only set of connected openings, then the body would be homeomorphic to a torus.

    However, there's a complex set of connected openings in the head: 2 nostrils, 2 tear ducts, and the mouth all connect to each other inside. I don't know what this is referred to as, topologically. Perhaps someone can help me out here. I'm guessing it's a quad-torus, and combined with the hole above makes the total a quintuple-torus?

    We do, of course, assume that no other piercings have been made.

  27. Re:Summary of the Poincare conjecture is inaccurat by Anonymous Coward · · Score: 0

    For your next trick, maybe you can learn to use the apostrophe correctly? Who's means WHO IS.

  28. Re:what about... by assert(0) · · Score: 1
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  29. Where's Obama's? by Anonymous Coward · · Score: 0

    Why hasn't Obama got this prize?

    Damn Republicans.

  30. A triumph for Perelman by amightywind · · Score: 1

    A triumph for Perelman. I hope he accepts the prize and rejoins the mathematical world. It is a little surprising that Hamilton did did share it as the Ricci flow was a crucial idea. But there is no doubting that Perelman did the heavy lifting.

    For those of you who dismiss this result is of little worth, you will not likely see a comparable achievement of the human mind for 50 years.

    --
    an ill wind that blows no good
  31. Re:Layman's terms? by Wizard+Drongo · · Score: 1

    Apparently people didn't watch "Event Horizon".
    And they call themselves nerds!

    --
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  32. Take away my Slashdot card by blake182 · · Score: 1

    Can someone please hyperlink every word of this article to Wikipedia for me?

    I'll show myself the door. Pout.

  33. His ethnicity: Jewish. by Anonymous Coward · · Score: 0

    It should be noted, that though he is from Russia, he is not Russian, but a Jew. Russia, a country full of anti-semites, yet still and once again, only a Jewish Scientist is able to make a break through of such magnitude. Perelman, I salute you, You join the ranks of Feynman, Einstein, Neuman and many others who have literally created modern Physics, Cybernetics, Mathematics, and everything else that is Science and technology.

  34. He turned it down by Frans+Faase · · Score: 1

    According to this news announcement Perelman turned down the price offer saying "he had all he wanted." and that "he is not interested in money or fame."

    1. Re:He turned it down by Frans+Faase · · Score: 1

      According to this news item he has not made up his mind yet.