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The Almighty Buck Science

Mathematician Claims Proof of Riemann Hypothesis 561

TheSync points to this press release about a Purdue University mathematician, Louis de Branges de Bourcia, who claims to have "proven the Riemann hypothesis, considered to be the greatest unsolved problem in mathematics. It states that all non-trivial zeros of the zeta function lie on the line 1/2 + it as t ranges over the real numbers. You can read his proof here. The Clay Mathematics Institute offers a $1 million prize to the first prover."
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Mathematician Claims Proof of Riemann Hypothesis

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  • by Anonymous Coward on Wednesday June 09, 2004 @07:06PM (#9382582)
    Karma-whoring free [216.239.39.104].
  • Failed proof (Score:5, Informative)

    by MobyDisk ( 75490 ) on Wednesday June 09, 2004 @07:06PM (#9382584) Homepage

    Ha! They've already found an error in the proof! All that he posted was his apology! [purdue.edu] :-)

    Yes, I was actually confused at first. For the non-math geeks like myself, who are feeling stupid, look at definition 2a of apology [reference.com].
  • He is very brave (Score:2, Informative)

    by Anonymous Coward on Wednesday June 09, 2004 @07:07PM (#9382594)
    The paper is called, Apology for the proof of the Riemann hypothesis (in pdf format). [purdue.edu] To find the apology you have to read through to page 4 where he talks briefly about the problems that the solution of a celebrated problem creates for others who weren't expecting it. Basically the title is, "a form of Mathematical smack talk" (to quote a co-worker).

    Most of the paper appears to be history, and the results leading up to his proof. Only a few pages at the end make up the actual new proof, so the novel material is far shorter than 23 pages.

    I wouldn't be surprised if there is a fairly final verdict on his proof very quickly. This is not like Wiles' proof of Fermat that was very long and nobody had the background to understand. This proof looks reasonably short and straightforward.

    Cheers,
    Ben Tilly
  • WTF? Mods? (Score:5, Informative)

    by Unnngh! ( 731758 ) on Wednesday June 09, 2004 @07:10PM (#9382613)
    From reference.dictionary.com:

    Apology - 2: a formal written defense of something you believe in strongly

    This should at most have earned a "Funny", or is there something I'm missing here?

  • Re:Apology (Score:4, Informative)

    by ssssmemyself ( 709098 ) on Wednesday June 09, 2004 @07:13PM (#9382635) Homepage
    Note to mods: Mod parent funny, not interesting! This is a play off a quote from the beginning credits sequence in Monty Python and the Holy Grail. As for the pdf link, it's the first link in the purdue page referenced in the article. RTFA, people!
  • by Anonymous Coward on Wednesday June 09, 2004 @07:16PM (#9382664)
    The Riemann Hypothesis, among other things, implies that the Prime Number Theorem is off in the distribution of primes by no more than O(sqrt(n)*log(n)). However even without the full result, we already had very good error bounds for the approximation of the prime number theorem for "small" numbers, including numbers far larger than any which come up in cryptography.
  • Re:Impact on crypto? (Score:3, Informative)

    by Unnngh! ( 731758 ) on Wednesday June 09, 2004 @07:19PM (#9382683)
    I don't know nearly enough math to understand the proof, but judging that the hypothesis was made by Reimann quite a while ago, and this is a proof of that hypothesis, I would conclude that the theory has been extant but unsubstantiated until now.

    So, in short, no, no help for cracking crypto based on primes...though the article does mention possible crypto applications down the line. I'm not sure what, exactly, those would be.

  • Re:Impact on crypto? (Score:4, Informative)

    by mdrejhon ( 203654 ) * on Wednesday June 09, 2004 @07:23PM (#9382714) Homepage
    The art of cryptography can be summed up as: Easy to encode, but hard to decode.

    Prime numbers are easy to multiply together. Little CPU needed.

    But it's hard to do the reverse: Factor a big number into two separate prime numbers. Lots of CPU needed.

    It's based on that principle.
  • by k98sven ( 324383 ) on Wednesday June 09, 2004 @07:28PM (#9382760) Journal
    Sorry to burst the bubble, but some usenetting shows:

    The same guy claimed [google.com] to have solved the same problem at least 4 years ago.
    The guy has a reputation [google.com] for sometimes getting it wrong.

    (Probably because he has published flawed proofs [google.com] of other well-known problems.)

    He could be right, but I wouldn't get my hopes up.
  • Re:Impact on crypto? (Score:3, Informative)

    by Mahrtian ( 238199 ) <dallas@@@mahrt...org> on Wednesday June 09, 2004 @07:30PM (#9382778)
    The magic of PKI occurs through the use of extremely long prime numbers, called keys. Two keys are involved - a private key, which only you have access to, and a public key, which can be accessed by anyone. The two keys work together, so a message scrambled with the private key can only be unscrambled with the public key and vice versa. The more digits in these keys, the more secure the process. --Public-key encryption for dummies [nwfusion.com]

    Not the best explanation, I prefer this [amazon.com]
  • The Problem (Score:5, Informative)

    by Anonymous Coward on Wednesday June 09, 2004 @07:31PM (#9382788)
    The problem is simple enough to understand, assuming you know some math basics. As most of you know, any function f(X) where f(Xo)=0 is said to have a zero at Xo. For functions of complex numbers f(z) where z=x+iy and x,y are real numbers, you obviously have the function taking on different values for every x and y, so the zeros can be anywhere on the x-y plane. For the zeta function, "trivial zeros" occur at the negative even integers (z=-2+i0,-4+i0,...) and also at points on the line x=1/2 (i.e 1/2 +iy for certain y).The Riemann Hypothesis says that all zeros that aren't negative even integers lie on this line.

    Most of you have who have taken basic calculus courses have probably seen a simplified definition of the zeta function for real intergers greater than 1. when z=n, a natural number, the zeta function reduces to the infinite series Zeta(n)= SUM (k=1-->inf) 1/k^n
  • by Anonymous Coward on Wednesday June 09, 2004 @07:33PM (#9382793)
    Nope, probably not.
    Most mathematicians felt that the Riemann Hypothesis was true so that this view has been taken into consideration into mathematics for a long time. Perhaps if he developed some new methods for playing with numbers in the proof, but it doesn't seem like it to me.
    There's a ton of math papers that begin with "Assume the extended riemann hypothesis...".

    At least that's my guess.
  • Re:Impact on crypto? (Score:4, Informative)

    by cperciva ( 102828 ) on Wednesday June 09, 2004 @07:36PM (#9382819) Homepage
    One of the fallout corollaries from a proof of the Riemann hypothesis is that there exists a simple algorithm for factorization (read: p-time).

    No. GRH implies that isprime() is in P (by bounding the cost of a strong pseudoprime test); but we already knew that, thanks to AKS.
  • Re:Impact on crypto? (Score:5, Informative)

    by susano_otter ( 123650 ) on Wednesday June 09, 2004 @07:37PM (#9382824) Homepage
    This theorem is a theory of how prime numbers are distributed...

    It's actually a little more complex than that.

    Riemann was investigating the distribution of prime numbers. Along the way he devised (discovered?) the Zeta Function, which describes with considerable accuracy the distribution of prime numbers. While working with the Zeta Function, he discovered an interesting property: It appeared that all the non-trivial zeroes of the function had a real part of one-half. However, since this property of the function was not related to the prime-distribution work he was doing, he did not bother to prove this apparent property, which came to be known as the "Riemann Hypothesis" (presumably, once it is proven it will be known as the Riemann Theorem, or some such).

    Thus, the Riemann Hypothesis is in fact tangential to (and possibly unrelated to) the distribution of prime numbers. Riemann's notes on the Zeta Function, regarding his work on prime distribution, are pretty explicit about this.

  • Re:Impact on crypto? (Score:5, Informative)

    by cperciva ( 102828 ) on Wednesday June 09, 2004 @07:39PM (#9382841) Homepage
    does it's proof have any impact on crypto?

    No. Almost all mathematicians have assumed for years that GRH is true anyway; proving it would mean that all those footnotes ([1] Under the assumption of the Riemann Hypothesis) could be removed, but that's the only practical effect it would have.
  • Re:Proof of theory (Score:3, Informative)

    by Tom7 ( 102298 ) on Wednesday June 09, 2004 @07:43PM (#9382873) Homepage Journal
    Dude, what the fuck are you talking about?

    Mathematicians tackle difficult problems all of the time, regardless of the (lack of) money involved.

    I don't know why you say that interest in "theoretical" mathematical proof is waning. It certainly isn't where I come from. (And what is ultra-math??!)
  • Usage of "apology" (Score:3, Informative)

    by mhotas ( 680248 ) on Wednesday June 09, 2004 @07:45PM (#9382890)
    This usage of "apology" is fashionable in math circles; a prime example is the title of G. H. Hardy's memoir : A Mathematician's Apology [brothersjudd.com].
  • actual paper (Score:5, Informative)

    by Anonymous Coward on Wednesday June 09, 2004 @07:48PM (#9382909)
    The 23 page "apology" is not the actual purported proof, contrary to what the article and press release say. The actual proof is the manuscript "Riemann zeta functions", the third link on de Branges' home page, which weighs in at 124 pages!

    So if his "proof" isn't obviously wrong, it'll likely take quite a while for the experts to verify.
  • by roll_w.it ( 317514 ) on Wednesday June 09, 2004 @07:49PM (#9382911)
    otoh, he proved the Bieberbach conjecture in 84 and has been working on this since. Perhaps this is why he posted it before it is formally published in a journal.
  • by mrthoughtful ( 466814 ) on Wednesday June 09, 2004 @07:56PM (#9382957) Journal
    Well, he is reliably credited with solving the Bieberbach conjecture - the guy isn't a complete nut.

    However, a quick scan suggests that if his proof is indeed verified, it won't do what a lot of people want it to do: Quote from the article: "The proof of the Riemann hypothesis verifies a positivity condition only for those Dirichlet zeta functions which are associated with nonprincipal real characters. The classical zeta function does not satisfy a positivity condition since the condition is not compatible with the singularity of the function. But a weaker condition is satisfied which has the desired implication for zeros."

    So I may be wrong, but it looks like he may have found ground on a restricted interpretation of the GRH (or Generalized Riemann Hypothesis), -ie concerning Dirichlet zeta functions which are associated with nonprincipal real characters only.

    As for consequences, If GRH is indeed true, then e.g. the Miller-Rabin primality test is guaranteed to run in polynomial time.
  • by Phragmen-Lindelof ( 246056 ) on Wednesday June 09, 2004 @08:18PM (#9383083)
    I think you are going a bit overboard here. The Riemann hypothesis is the greatest open problem in mathematics right now and solving it would be HUGE :-). However, famous open problems usually do not advance mathematics that much and I suspect that a proof of the Riemann hypothesis would not introduce new techniques which would have wide (or even slightly wide) use in math. Look at some of the Fields metal papers (e.g. restricted Burnside problem - Zelmanov - 1994 metal) and tell me how they changed mathematics.
    For influences on math, consider Dirac (crazy British scientist who predicted to existence of the positron) whose ideas led L. Schwartz, L. to write "Théorie des distributions. Tome I,II"; distribution theory has had a huge influence on analysis.
  • Re:verification (Score:1, Informative)

    by Anonymous Coward on Wednesday June 09, 2004 @08:19PM (#9383090)
    Unlike what the other 2 people say, this is *not* an impossible ("undecidable") problem. Computers *can* formally verify any proof. The problem is that the complexity of such a program would be huge, and it would take a lot of time to make.

    *Creating* proofs is the hard part, and was proven undecidable. But verifying ones that exist is not.

    Melissa <3
  • by jim3e8 ( 458859 ) on Wednesday June 09, 2004 @08:38PM (#9383184) Homepage
    The 23-page "Apology" referred to in the press release is also apparently mentioned in this 1996 Usenet post [google.com]. So is there a new proof? No one seems to know yet.
  • by Anonymous Coward on Wednesday June 09, 2004 @08:45PM (#9383218)
    A cool overview of why this is such an interesting hypothesis [ex.ac.uk].

    If nothing else check out the animation [ex.ac.uk].

    mind-boggling
  • by Anonymous Coward on Wednesday June 09, 2004 @08:59PM (#9383273)
    The Riemann Hypothesis is a pain to explain before getting into some complex stuff about complex analysis (calculus involving complex numbers; IE numbers involving i = sqrt(-1)). I'm going to show the Riemann Hypothesis in the simplest terms possible, something that calculus students could understand (though not prove, of course!).

    The Riemann hypothesis states that if this function:

    sum from n=1 to infinity ((-1)^(n+1) / n^(x+iy))

    equals zero, then x = 1/2 . x and y are variables; x+iy is a complex number normally labeled "z".

    If you don't want to deal with complex numbers, you can use the equivalent statement about real numbers: If the following function:

    (sum from n=1 to infinity ((-1)^(n+1) * cos(y*ln(n)) / n^x))^2 + (sum from n=1 to infinity ((-1)^(n+1) * sin(y * ln(n)) / n^x))^2)

    equals zero, then x = 1/2 . The following URL is a picture of the above in normal notation so it's easier to read:

    http://www.geocities.com/myriachan/riemann.png

    Melissa <3
  • Re:WTF? Mods? (Score:1, Informative)

    by asl24 ( 750888 ) on Wednesday June 09, 2004 @09:10PM (#9383312)
    This should at most have earned a "Funny", or is there something I'm missing here?

    Uh, yeah. I'm going to assume that the thing you missed was "Monty Python and the Holy Grail." [imdb.com] Or, at least the opening credits.
  • by Anonymous Coward on Wednesday June 09, 2004 @09:15PM (#9383326)
    I want to say 2 things about what I said above...

    1. The function I showed was *not* the Zeta function. That's because the standard 1 + 1/1^z + 1/2^z + ... 1/n^z notation does not converge for Re[z] 0), and its zeros by its definition are the nontrivial zeros of the Zeta function. It is the Dirichlet Eta function that I showed.

    2. The version not involving complex numbers is pretty easy to derive. Use "a^(b+c) = a^b * a^c", "e^ix = cos x + i sin x", "x^y = e^(y ln x)", and "cos^2 x + sin^2 x = 1", then separate out the real and imaginary parts. The square just acts as an absolute value here. A negative sign on the "sin" half is removed by the square/absolute value.

    Melissa <3
  • by SamSim ( 630795 ) on Wednesday June 09, 2004 @09:20PM (#9383356) Homepage Journal

    First: complex numbers [wolfram.com], explained. You may have heard the question asked, "what is the square root of minus one?" Well, maths has an answer and we call it i [wolfram.com]. i*i = -1. If the real number line ...-4, -3, -2, -1, 0, 1, 2, 3, 4... is represented as a horizontal line, then the numbers ...-4i, -3i, -2i, -i, 0, i, 2i, 3i, 4i... can be thought of as the *vertical* axis on this diagram. The whole plane taken together is then called the complex plane [wolfram.com]. This is a two-dimensional set of numbers. Every number can be represented in the form a+bi. For real numbers, b=0.

    Right. Now the Riemann Zeta Function [wolfram.com] is a function/map (like f(x)=x^2 is a function) on the complex plane. For any number a+bi, zeta(a+bi)will be another complex number, c+di.

    Now, a zero [wolfram.com] of a function is (pretty obviously) a point a+bi where f(a+bi)=0. If f(x)=x^2 then the only zero is obviously at 0, where f(0)=0. For the Riemann Zeta Function this is more complicated. It basically has two types of zeros: the "trivial" zeroes, that occur at all negative even integers, that is, -2, -4, -6, -8... and the "nontrivial" zeroes, which are all the OTHER ones.

    As far as we know, *all* the nontrivial zeroes occur at 1/2 + bi for some b. No others have been found in a lot of looking... but are they ALL like that? The Riemann Hypothesis [wolfram.com] suggests that they are... but until today nobody has been able to prove it.

  • Re:He is very brave (Score:2, Informative)

    by radicalaxis ( 610342 ) on Wednesday June 09, 2004 @09:45PM (#9383454)
    Hm. It appears that I did not notice that the real proof is in fact here [purdue.edu].
  • Re:Impact on crypto? (Score:2, Informative)

    by CarlCotner ( 156175 ) on Wednesday June 09, 2004 @09:46PM (#9383458)
    Uh, no.

    The truth (or falsity) of the Riemann Hypothesis is intimately related to the distribution of the primes. Specifically, if the RH is true, then the primes are distributed about as regularly as possible.[1]

    Carl

    [1] See, for example, equation (2) of Riemann Hypothesis [wolfram.com]

  • Re:Impact on crypto? (Score:5, Informative)

    by NonSequor ( 230139 ) on Wednesday June 09, 2004 @09:46PM (#9383460) Journal
    Along the way he devised (discovered?) the Zeta Function, which describes with considerable accuracy the distribution of prime numbers.


    Actually, as with most things Euler was the first to study it. The zeta function is also the simplest of a class of functions that Dirichlet studied Dirichlet L-series. There is also a Generalized Riemann Hypothesis that states that no Dirichlet L-series has zero with real part greater than 1/2.

    The Riemann Hypothesis is more than tangential to the study of the distribution of primes. There is a function derived from the distribution of the primes that can be expressed in terms of the non-trivial zeros of the zeta function. The Prime Number Theorem is also equivalent to the statement that the zeta function has no zeros with real part 1. The Generalized Riemann Hypothesis implies the weak form of Goldbach's conjecture (i.e. that any odd number greater than 7 can be expressed as the sum of three odd primes).
  • by radicalaxis ( 610342 ) on Wednesday June 09, 2004 @09:55PM (#9383513)
    This review of Karl Sabbagh's book The Riemann Hypothesis contains some background on De Branges. http://www.maa.org/reviews/sabbaghRH.html He sounds like quite a character, from that and from his "apology"... given recent trends, I wonder if someone might write a novel or play about him?
  • Re:Impact on crypto? (Score:2, Informative)

    by ben_white ( 639603 ) <ben AT btwhite DOT org> on Wednesday June 09, 2004 @10:22PM (#9383647) Homepage

    Many cryptosystems are based off of doing complex math based off of very large random prime numbers.

    No, cryptosystems are based off of simple math based on a pair of very large pre-selected (read not random) prime numbers that make up your public and private key.

    Cheers, Ben

  • by PeeCee ( 678651 ) on Wednesday June 09, 2004 @10:49PM (#9383787)
    Next he'll be solving problems that are NP-Complete. We'll have to re-write all our textbooks!

    Not to spoil your joke or anything, but actually, AFAIK, NP-complete problems are perfectly solvable. The problem is how long it takes to solve them in general (a certain instance of a problem could prove easy). They cannot be solved deterministically in polynomial time (i.e., quickly).

  • by Anonymous Coward on Wednesday June 09, 2004 @10:54PM (#9383806)
    For those who have no idea what the Bieberbach conjecture is, see http://mathworld.wolfram.com/BieberbachConjecture. html
  • by Anonymous Coward on Wednesday June 09, 2004 @11:29PM (#9383947)
    See "Riemann Zeta Functions" lower for the actual paper in question. The bibliography has a date of May 25th, 2004 at the top. This looks like a modification of a previous paper he had posted there for several years (his previous attempt.)
  • by This is outrageous! ( 745631 ) on Wednesday June 09, 2004 @11:30PM (#9383955)
    As others mentioned, de Branges has been claiming a proof along the same lines for years. He's hard to dismiss because he actually proved the Bieberbach conjecture -- a startling exception in the series of wrong proofs he's been famous for, before and since.

    The reasons why most specialists doubt that his approach can ever yield the result are well described in this paper [arxiv.org] from 1998:

    In this note, we shall (...) give examples showing that de Branges' positivity conditions, which imply the generalized Riemann hypothesis, are not satisfied by defining functions of reproducing kernel Hilbert spaces associated with the Riemann zeta function zeta(s)
    (i.e., despite the name, the "generalized RH" proved by de Branges actually did not include the standard RH as a special case.)
  • by Anonymous Coward on Thursday June 10, 2004 @01:40AM (#9384442)
    Mathworld [mathworld.com] has a link to a paper which claims de Branges' method of proof is invalid. Here is a direct link to the site with the paper. [arxiv.org]
  • by qpacberty ( 763389 ) on Thursday June 10, 2004 @01:47AM (#9384468)
    Berkeley Groks [groks.net] has an interview [berkeley.edu] that aired today with John Derbyshire [olimu.com] discussing the Riemann Hypothesis. He states that after talking with many mathematicians in the field, the prospects for a solution any time soon are quite low.
  • Probably a hoax: (Score:4, Informative)

    by usmcpanzer ( 538447 ) <usmcpanzerNO@SPAMhotmail.com> on Thursday June 10, 2004 @02:43AM (#9384687) Homepage
    mathworld.wolfram.com
    Riemann Hypothesis "Proof" Much Ado About Noithing A June 8 Purdue University news release reports a proof of the Riemann Hypothesis by L. de Branges. However, both the 23-page preprint cited in the release (which is actually from 2003) and a longer preprint from 2004 on de Branges's home page seem to lack an actual proof. Furthermore, a counterexample to de Branges's approach due to Conrey and Li has been known since 1998. The media coverage therefore appears to be much ado about nothing
  • by Scorillo47 ( 752445 ) on Thursday June 10, 2004 @03:18AM (#9384802)
    The proof (or, better said, the sketch of the proof) actually starts at the end of page 21, very close to the last page. The original work is actually pretty hard to find since it is buried in so many unrelated side notes.

    Here is the general outline:
    1) At the end of page 19 he mentions that "The positivity condition which is introduced implies the Riemann hypothesis if it applies to Dirichlet zeta functions."
    2) After some introduction of the quantum gamma functions that lasts two pages, the actual proof starts at the end of page 21 with the phrase "A quantum gamma function is obtained when is nonnegative. A proof of positivity is given from properties of the Laplace transformation."
    3) The proof ends in the middle of page 23 with the a verification that W(z) is a quantum gamma function with quantum q = exp(-2*pi), obtained from a spectral theory of the shift operator.

    Overall this is just a very brief sketch of the whole proof.

    BTW, to add gas on fire, here is an exceprt from mathworld.com, which surprisingly was missed by /. until now :-)

    http://mathworld.wolfram.com

    Riemann Hypothesis "Proof" Much Ado About Noithing (sic)
    A June 8 Purdue University news release reports a proof of the Riemann Hypothesis by L. de Branges. However, both the 23-page preprint cited in the release (which is actually from 2003) and a longer preprint from 2004 on de Branges's home page seem to lack an actual proof. Furthermore, a counterexample to de Branges's approach due to Conrey and Li has been known since 1998. The media coverage therefore appears to be much ado about nothing.

    The counterexample to Brangles approach can be reached here: http://arxiv.org/abs/math.NT/9812166
  • by h4rm0ny ( 722443 ) * on Thursday June 10, 2004 @03:55AM (#9384939) Journal
    It seems like the answer (well, we'll call it "i") has been proposed before anyone has shown if can really happen.

    Great Cthulhu help me, but I'm going to try and answer this for you.

    We have natural numbers - 1,2,3, ... - and people are happy with this. It's an abstract way of representing a real property. I have five oranges, I owe you four oranges. Natural.

    And then we have Zero and once upon a time this disturbed people. You grew up with it, you're happy with it; but we can see that it was less intuitive than 1,2,3, ... because it developed so much later and the greeks managed without it for quite a long time. It's not an abstraction in the same way that these other numbers are. People used to ask questions such as, 'how can something exist and yet be nothing?' 'How can zero x zero = zero since that means you have no zero's?' Can you prove that it does mathematically, right now? *

    And yet, the discovery (or creation ;) of Zero allowed people to abstract in new ways that produced real world results. The same can be said of Negative numbers which are even less intuitive. If I give you those four oranges mentioned earlier (not bloody likely since I'm writing this before breakfast), then that leaves me with one. But suppose I owe you six oranges? We can't carry out that operation with oranges, but the operation is useful in many other areas, the most obvious is probably money. You can be overdrawn for example - that's applied negative numbers. Is there really anti-money in your account? Well, yes, why not? It's just numbers, and numbers are an abstraction, a model of something if you like. It's perfectly normal to represent some properties as negatives. Try basic Newtonian physics - two bodies moving in opposite directions towards each other. You treat the momentum of one of them as negative and the other positive which lets you work out which direction they're going in after collision.

    Now perhaps at this point, you're nodding and saying 'yes, yes, I know that already.' If so, then good, because you've just understood the principle of a complex number. It's another abstraction that can't easily be represented in the real world (nuclear physicists shut up, please). And yet, it has very real use in making calculations.

    If you're a programmer, think about how much code there is behind the scenes of a program to produce the result you want from it. Suppose that your program counts how many oranges people have given you. Maybe it has the line
    for (i=0; i &lt oranges_owed; i++) {}

    Well i isn't physically real, it doesn't represent a physical aspect of what you are modelling (the oranges) but it's useful. And in the same way, i is also useful, even if it's just part of a intellectual model.

    For a mathematician: I think therefore i is.

    The only thing remaining is to give you an example of how it is useful. Easily done - Quantum Physics. All of it. ;)

    Hope this helps, IASNAM (I Am Surprisingly Not...)


    * Proof that 0x0=0:
    0=1x0

    0=(0+1)x0
    0=0x0+1x0
    0=0x0+0
    0=0+0x0
    0=0x0
  • Re:Impact on crypto? (Score:1, Informative)

    by Anonymous Coward on Thursday June 10, 2004 @04:31AM (#9385033)
    It should be noted that while mathematicians often assume non-trivial things, they always need to keep track of their assumptions. You can't just say that we know XYZ theorem is true, you must always note that what you're stating is only true if Riemann's hypothesis is assumed. Keeping track of what assumptions you are relying on, is actually one of the most important skills a mathematician must have, and it sure would be nice if non-scientists would learn to do it.
  • by smallfries ( 601545 ) on Thursday June 10, 2004 @07:19AM (#9385506) Homepage
    It would appear that mathworld.com agrees with you...

    ----------------

    Riemann Hypothesis "Proof" Much Ado About Noithing
    A June 8 Purdue University news release reports a proof of the Riemann Hypothesis by L. de Branges. However, both the 23-page preprint cited in the release (which is actually from 2003) and a longer preprint from 2004 on de Branges's home page seem to lack an actual proof. Furthermore, a counterexample to de Branges's approach due to Conrey and Li has been known since 1998. The media coverage therefore appears to be much ado about nothing.
  • by JadeNB ( 784349 ) on Thursday June 10, 2004 @08:22AM (#9385757) Homepage
    * Proof that 0x0=0: 0=1x0 0=(0+1)x0 0=0x0+1x0 0=0x0+0 0=0+0x0 0=0x0

    This is fine as a proof that 0 x 0 = 0 once you know that 1 x 0 = 0. The proof (of either) is roughly as in your second and third lines:

    a x 0 = a x (0 + 0) = a x 0 + a x 0

    Cancelling a x 0 from both sides (which we may do, since we're in a group) gives a x 0 = 0.

  • by PastaLover ( 704500 ) on Thursday June 10, 2004 @08:43AM (#9385843) Journal
    NP-Complete problems are by definition problems that can't be solved in polynomial time(at least not by a Turing machine?). However, most problems that are considered NP-Complete are not mathematically proven to be so. Some are though, and the thing with NP-Complete problems is that you can always translate one NP-Complete problem to another NP-Complete problem.

    So in practice, NP-complete problems can be solved (you can solve just about anything by just trying every single solution) but for very big instances you will need several times the age of the universe etc.

    Several other posters in this thread seem to be mistaken about what the term actually means, but they were being so vague I thought I'd write this up. :)
  • by Anonymous Coward on Thursday June 10, 2004 @08:58AM (#9385938)
    The definition of NP-Complete has nothing to do with whether the problem can be solved in polynomial time. NP-Complete problems are the hardest of the class of problems in the set NP. The set NP is defined as all problems whose solutions can be verified in polynomial time. It hasn't been proven whether or not NP-Complete problems can or cannot be solved in polynomial time. Because of the way the proofs have been constructed, if you can solve any of the NP-Complete problems in polynomial time, you can solve all of them in polynomial time. That's why it is considered unlikely that any of the NP-Complete problems has a polynomial time solution, but it hasn't been proven.
  • by Deliberate_Bastard ( 735608 ) <`doslund' `at' `cs.ucr.edu'> on Thursday June 10, 2004 @09:18AM (#9386078)
    The definition of NP-Complete has nothing to do with whether the problem can be solved in polynomial time.

    Not quite correct, because:

    The set NP is defined as all problems whose solutions can be verified in polynomial time

    ...is one of *two* equivalent definitions of the class NP. The other is:

    "Set of all problems which can be solved in polynomial time by a nondeterministic Turing Machine."

    So the question "Does P equal NP?" is also the question "Does an NTM have the same computional power(in time) as a TM, or does it have more?" (It is already known that as far as decidiblity is concerned, TMs and NTM are equivalent.)

    Because of the way the proofs have been constructed, if you can solve any of the NP-Complete problems in polynomial time, you can solve all of them in polynomial time.

    Some more detail here:

    An NP-hard problem is a problem to which any problem in NP can be reduced in polynomial time.

    (Essentially, it can be used as a subroutine for any NP problem, with only a polynomial number of calls. Thus a solution to it is a solution to any problem in NP.)

    An NP-complete problem is one that is:

    1. NP-hard
    2. In the set NP.

    Thus if a polynomial-time solution exists to an NP-complete problem, then P=NP, because a polynomial number of calls to a function that terminates in polynomial time is O({polynomial}*{polynomial}) = O({polynomial}) .

    Please note, however, that not all NP-hard problems are NP-complete.
  • by Stephan Schulz ( 948 ) <schulz@eprover.org> on Thursday June 10, 2004 @09:50AM (#9386361) Homepage
    NP-Complete problems are by definition problems that can't be solved in polynomial time(at least not by a Turing machine?). However, most problems that are considered NP-Complete are not mathematically proven to be so. Some are though, and the thing with NP-Complete problems is that you can always translate one NP-Complete problem to another NP-Complete problem.
    Sorry, but you got things mixed up.

    NP problems are problems that can be solved by a Nondeterministic Turing machine in Polynomial time. NP-Complete problems are the class of "hardest" problems in NP. All the usual suspects (Traveling Salesman, 3-SAT, SAT, ...) are proven to be in NPC.

    We know that we can solve NPC problems in exponential time (as we can simulate a non-deterministic Turing maschine on deterministic hardware with exponential overhead). What we do not know is if there is any smarter way. That is the P=?=NP question.

  • Well, not exactly (Score:4, Informative)

    by mrgeometry ( 689087 ) on Thursday June 10, 2004 @10:00AM (#9386449)
    Sorry, but...

    It is not proved; he is not at the top of his field; this "paper" will be quickly forgotten among professional mathematicians; and I doubt any professional mathematician is going over the proof with any sort of comb.

    L. de Branges first achieved fame for proving the Bieberbach conjecture [wikipedia.org]. His proof went through strange and abstract methods. He went on the road to present his proof at various seminars in France, Russia, etc; IIRC a bunch of Russian students got very excited and basically rewrote his proof. Their new proof was much shorter and avoided the use of strange methods. Nowadays, their proof is remembered and his is not, but the proof still bears his name, since after all he was the first to come up with *some* kind of proof, and their proof did more or less come out of his.

    So he deserves credit for that, and it was quite an achievement to prove the Bieberbach conjecture. But even then he was using unwieldy proofs with unnecessarily abstract methods.

    For many years he has been claiming to have a proof of the Riemann Hypothesis. Professional mathematicians stopped listening a long time ago.

    This guy is washed-up.

    I whole-heartedly agree that this short article is hilarious, but I would like to add the adjective condescending. What kind of asshole apologizes for solving a problem? Does he think he lives on some higher plane, and therefore must take direct, personal responsibility for every aspect of our lives?

    Look at how G. Perelman submitted his ideas on proving the Poincare conjecture [wikipedia.org] just a little while ago. He didn't waste anyone's time by rehashing the already-available history of the problem or its wider context in mathematics. Nor did he apologize for having an idea. Rather, he submitted his ideas for consideration, with the full awareness that there may have been a mistake. .... Now, this is where I admit that I do not really understand that area of math, and have not been closely following the status of (alliteration alert) Perelman's proposed proof. Still, Perelman is a real mathematician, and even if the proof is (was?) wrong, it has real ideas of value in it.

    de Branges is so full of crap, it makes me sick.

    zach
  • by henrygb ( 668225 ) on Thursday June 10, 2004 @10:36AM (#9386953)
    Not the safest way to be convinced.

    For example, try looking at the difference between n^n and the largest factorial less than or equal to it. This starts 1^1-1!=0, 2^2-2!=2, 3^3-4!=3,... and goes on 136, 2405, 6336, 460663, 13148416, 347503689,... which looks as if it is increasing. Keep going, and it still looks as if it is increasing, but keep going and after more than 4 million steps you are dealing with numbers with around 30 million decimal digits when it suddenly takes a small step down.

  • by saforrest ( 184929 ) on Thursday June 10, 2004 @10:36AM (#9386964) Journal
    NP-Complete problems are by definition problems that can't be solved in polynomial time(at least not by a Turing machine?).

    No, you're wrong. NP problems are, by definition, problems that can be solved in polynomial time by a nondeterministic Turing machine [wikipedia.org].

    Essentially this means that a Turing machine could solve the problem in polynomial time, if it had some magic 'oracle' which instructed it on the right computational path to follow for a given input.

    Obviously there are problems out there that would require exponential time for even a nondeterministic Turing machine to solve. An example from the Wikipedia link I provided is finding the best move in a chess or Go game.

    Such problems are not in NP, and proving P=NP would not suddenly give us algorithms for solving these problems deterministically in polynomial time.

    However, most problems that are considered NP-Complete are not mathematically proven to be so.

    What? Sorry, if there ain't a proof, it ain't NP-complete. There are a lot of problems that are described as "believed to be NP-complete", but that's different.

I find you lack of faith in the forth dithturbing. - Darse ("Darth") Vader

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