Stories
Slash Boxes
Comments

News for nerds, stuff that matters

Slashdot Log In

Log In

Create Account  |  Retrieve Password

There Are Infinitely Many Prime Twins

Posted by michael on Fri May 28, 2004 05:49 PM
from the so-the-theory-goes dept.
fustflum writes "R. F. Arenstorf from Vanderbilt University has presented a 38-page possible proof of the twin-prime conjecture using methods from classical analytic number theory. The paper is on arxiv.org and is freely available to the public. Twin primes are pairs of primes where both p and p + 2 are prime. "It is conjectured that there are an infinite number of twin primes ... but proving this remains one of the most elusive open problems in number theory." More information about twin primes can be found on Mathworld."
+ -
story
This discussion has been archived. No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
 Full
 Abbreviated
 Hidden
More
Loading... please wait.
  • but proving this remains one of the most elusive open problems in number theory

    I think we all know the most elusive open problem in number theory is "How many licks does it take to get to the center of a tootsie pop?"

    • by DarkHelmet (120004) * <mark.seventhcycle@net> on Friday May 28 2004, @05:53PM (#9281775) Homepage

      Let's leave the proof to Physics:

      One... two... three... *BITE*

      ............Three.

    • by Da Fokka (94074) on Friday May 28 2004, @06:18PM (#9281929) Homepage
      Reminds me of a funny story I heard at an algorithm course in college.
      Supposedly this guy thought up this new algorithm to calculate large primes in relatively short time. He was granted the use of the university mainframe. He implemented the progam and ran it.
      After a couple of days the printer started printing out the number, which was so large it needed a pack of sheets to fit on.
      Excited, he looked at the sheets to be gravely disappointed. The last digit was an 8.

      Probably an urban legend, but a nice one for sure :)
    • Re:Number theory (Score:4, Interesting)

      by sbaker (47485) * on Friday May 28 2004, @10:54PM (#9283182) Homepage
      My son figured this out - with the help of some Lego - the answer is 332 (except for the Cherry ones that take a few less):

      http://www.sjbaker.org/gallery/lickomatic/index.ht ml
  • One smart dude (Score:5, Informative)

    by overbyj (696078) on Friday May 28 2004, @05:52PM (#9281760)
    I was a grad student at Vanderbilt in a different department but I had some friends in math that really knew this guy. Needless to say, this guy is brilliant. I don't really know much about his work but honestly, I am surprised it took him as long as it did to do this.

    Score another for number theory thanks to this dude.
    • Re:One smart dude (Score:5, Insightful)

      by fatphil (181876) on Friday May 28 2004, @06:11PM (#9281898) Homepage
      Slow down!
      It's not been reviewed yet.

      I'm waiting until Granville, Odlyzko, Mihailescu, or someone similar gives it the thumbs up.
      However, it's not obvious tosh, and therefore if it does have flaws it may well be correctible, or at least provide new insight.

      The guy certainly _was_ brilliant, but given that he started his peak in the mid-60s, there's no guarantee he's still at it.

      FP.
    • by b0r0din (304712) on Friday May 28 2004, @06:27PM (#9281989)
      Look on page 27. He's trying to integrate homeomorphic convergence using a Baxter-Bates supermodality, which Krause clearly explained is impossible for T(s) in a non-linear progression.

      Ok, just fuckin with ya. My mind wandered after I saw the word 'Abstract.' ;)
      • by Anonymous Coward on Friday May 28 2004, @07:19PM (#9282317)
        Yeah, I see a lot of people attempting to integrate homophobic conformance using Master-Bates supermoodality, which Krauds exploded as impenetrable for T/bag in a non-lesbian prostation.
  • This stuff is so fascinating that I'm just sure I'll be the life of the party when I start talking about it!

    "You know, mathematicians theorize that there's an infinite number of prime twins, and... hey, where are you going?"
  • Old news (Score:5, Funny)

    by Hamster Of Death (413544) on Friday May 28 2004, @05:52PM (#9281766)
    Glancing at my list of twin primes I can see it's infinite.
  • by Anonymous Coward on Friday May 28 2004, @05:52PM (#9281771)
    but it hit /.'s maximum post size limit :(
      1. Given: There are infinitely many primes.
      2. Given: A certain positive percentage of primes differ by two.
      3. Given: Infinity times any positive number is infinity.
      4. Therefore: There are infinitely many primes that differ by two.
      That's my story and I'm stickin' to it.

      (Spot the logical error and you win a cookie!)
      • by hoggoth (414195) on Friday May 28 2004, @06:37PM (#9282057) Journal
        > 2. Given: A certain positive percentage of primes differ by two.

        Not necessarily true. It's equally possible that a certain finite number of primes differ by two, not an infinite percentage of primes.

        Give me my cookie now.
        • It's equally possible that a certain finite number of primes differ by two, not an infinite percentage of primes.

          Talking about infinite percentages is meaningless. Think about this question - what percentage of all natural numbers are even? On the one hand, it seems that since every second number is even, there would be 50%, right? But what if I pair each and every natural number to an even number so that two different numbers are paired to different even numbers (a one-to-one map)? Would that mean that 100% of all natural numbers are even? But it is done easily - I would pair each number n to 2*n.

          You could try and wiggle out of this problem by defining the infinite percentage to be the limit of the normal percentage until N when N goes to infinity. This would work for some sets, like the even numbers and would even give you a seemingly reasonable answer - 50%. But then consider this question - what percentage of all natural numbers are powers of 2 by this definition? I'll leave that as an exercise to the reader :-)

          See Cardinality [wikipedia.org]

            • I'll explain it like my prof. did :-)

              Imagine you arrive at a party and see that some number of men and women are dancing in pairs - each woman is dancing with one man and each man with one woman. You can immediately observe, without counting the actual number of men and women that there is an equal amount of them, right? The same idea is applied to sets (even infinite ones) - if you can pair each element in set A to an element in set B in such a way that each element in B has a pair in A then the two sets have the same "amount" (cardinality is the mathematical term) of elements.

              Now, let's take A to be the set of all natural numbers and B to be the set of all even natural numbers. I will then pair each natural number n, to an even number - 2*n. Now, each even number N has a pair - N/2, so we conclude that the "amount" of even numbers equals the "amount" of natural numbers (100% of them, by the naive definition).

              You might conclude from this that any two infinite sets have the same "amount" of elements, which seems true at first glance - after all, infinity is infinite, so surely there will be enough elements in any infite set to pair to the elements of another infinite set! This, however, turns out to be wrong. For example, there are "more" real numbers than there are natural numbers. That is, there exists no one-to-one and onto function (Bijection [wikipedia.org]) from the set of natural numbers to the set of real numbers.

        • by Atario (673917) on Friday May 28 2004, @07:55PM (#9282473) Homepage
          Ding ding ding! We have a winnah!

          You will find your cookie on your hard drive, assuming you're logged in to Slashdot.
      • You can't assume that a certain positive percentage of *all* primes differ by two as stated in number two, because that's an analogous statement to what you're trying to prove.

        Say I have an infinite number of socks. All are white, except 3, which are grey. I have a positive percentage of grey socks, but that doesn't mean anything since that percentage is infinitessimal. It will be infinitessimal for any number of grey socks, so you can't say that you are assumed have a positive percentage of grey socks *unless* you have an infinite number of grey socks, and that's a tautological argument.

        Chocolate chip, please ;)
  • by Timesprout (579035) on Friday May 28 2004, @05:54PM (#9281795)
    possible proof of the twin-prime conjecture

    The words possible and conjecture appear above. Where does the definitive statement "There Are Infinitely Many Prime Twins" come into it? Have the the /. editors secretly managed to prove this theory before posting it ?
    • Peer Review (Score:5, Informative)

      by Kozar_The_Malignant (738483) on Friday May 28 2004, @06:43PM (#9282092)
      The author is saying, in effect, "I think I have a proof here. Have at it." His esteemed colleagues, including jealous backstabbers, hacks who have failed at the same problem, and a relatively small number of really first rate mathemeticians will try to show he is wrong. Consensus will emerge one way or another. The editors are, I'm sure, simply offerring the collective genius of /. a change to join the fray.
  • 38 pages? (Score:5, Funny)

    by Wakkow (52585) * on Friday May 28 2004, @05:57PM (#9281808) Homepage
    They should have put it in 37 pages..
  • by robbo (4388) <slashdot.simra@net> on Friday May 28 2004, @05:59PM (#9281818) Homepage
    they're all odd.

    (Waiting for my spot in the math hall of fame)
  • by micha2305 (769447) on Friday May 28 2004, @06:00PM (#9281828)
    Something I read in Science [sciencemag.org] the other day: There's a new proof in review that there are infintely many sequences such as 199, 409, 619, 829, 1039, 1249, 1459, 1669, 1879, 2089 -- primes that differ by a constant offset. See also Mathworld [wolfram.com].
      • by aardvarkjoe (156801) on Friday May 28 2004, @06:35PM (#9282046)
        Quoting directly from the linked article:
        An arithmetic progression of primes is a set of primes of the form p1 + kd for fixed p1 and d and consecutive k, i.e., {p1, p1 + d, p1 + 2d, ...}. For example, 199, 409, 619, 829, 1039, 1249, 1459, 1669, 1879, 2089 is a 10-term arithmetic progression of primes with difference 210.


        In a recently published in preprint, Green and Tao (2004) use an important result known as Szemerédi's theorem in combination with recent work by Goldston and Yildirim, a clever "transference principle," and 48 pages of dense and technical mathematics, to apparently establish the fundamental theorem that the prime numbers do contain arithmetic progressions of length k for all k (Weisstein 2004).

        Take it for what it's worth. This stuff is way over my head.
  • by RealAlaskan (576404) on Friday May 28 2004, @06:02PM (#9281842) Homepage Journal
    That's ``twin primes'', not ``prime twins''. So, no, there is not an infinite supply of hot double dates.
  • Alien (Score:4, Funny)

    by Juiblex (561985) on Friday May 28 2004, @06:03PM (#9281845)
    In what Alien language is the article written???

  • twins (Score:5, Funny)

    by sacrilicious (316896) on Friday May 28 2004, @06:08PM (#9281884) Homepage
    Twin primes are pairs of primes where both p and p + 2 are prime.

    Even rarer are those pairs of primes known as the "conjoined twin" primes: those of the form p and p+1. Not many examples are known, but perhaps an infinite number are waiting to be discovered.

    • There are no "conjoined twin" primes other than 2 and 3. Rather trivial proof follows:
      • Assume p and p+1 to be primes, and p>2
      • Since p is prime and greater than 2, it does not have 2 as a factor, therefore it is odd
      • Since p is odd, p % 2 = 1
      • Since p % 2 = 1, (p + 1) % 2 = 0
      • Therefore (p + 1) is even, therefore (p + 1) has 2 as a factor, therefore (p + 1) is not prime
      • Therefore by contradiction, no conjoined twin primes exist other than (2,3)
  • by gwoodrow (753388) on Friday May 28 2004, @06:14PM (#9281909)
    I tried to read through some of the paper and math websites... and I was suddenly reminded why the diploma that will be handed to me at the end of the summer will say:
    "Steven Gregory Woods... ENGLISH major"
    Hopefully, math will turn out to be just a fad :)
  • This took 20 years (Score:5, Informative)

    by ortholattice (175065) on Friday May 28 2004, @06:25PM (#9281977)
    Interesting quote from the paper (p. 3 of the PDF file):
    This work is the outcome of about twenty years of "on and off" search and research on this and the related binary Goldbach problem; in the interim having been lured onto various misleading paths or frustrated by (for me) insurmountable difficulties, before ultimately recognizing and constructing a workable approach.
  • by CoolGuySteve (264277) on Friday May 28 2004, @06:31PM (#9282017)
    The sum of any two consecutive odd numbers is divisible by 4. I misread a question in first year and proved it.

    I thought that was fairly neat, it makes me the life of the party when I tell it to people. (Well, not really. Depressing.) Does anyone know any other little tricks like that?
    • Here's an interesting one, this is guarenteed to piss off any math student that doesn't get it.

      if a=b, then:

      a^2=ab
      a^2-b^2=ab-b^2
      (a-b)(a+b)=b(a-b)
      a+b=b

      substitute in the original a=b equation

      2a=a
      2=1

      wtf? So where's the error? :)

      • by Sycraft-fu (314770) on Saturday May 29 2004, @12:11AM (#9283409)
        "So where's the error?"

        I'm guessing that's a rhetorical question, but the error is you divide by zero. On line three you are actually are showing 0=0 since anything minus itself is zero and anything times 0 is 0. You then try to divide out (a-b), which is zero, and can't be done.

        I can see this fooling people who aren't good at math but probably not math students. It's not like I ever got very far in math, and the problem is easy to spot.
  • by geordieboy (515166) on Friday May 28 2004, @07:06PM (#9282245)
    I propose the geordieboy conjecture:

    There are an infinite number of prime n-pairs, where
    an n-pair is a pair of prime integers (p,p+n).

    I also propose geordieboy's second conjecture:

    There are an infinite number of prime tuples, where a prime
    tuple is a set of prime integers of the form (p+a,p+b,p+c,...)
    where (a,b,c,...) is a set of any integers of your choosing.

    Get stuck in you poor bastards!
  • amazing if it's true (Score:5, Interesting)

    by cancerward (103910) on Friday May 28 2004, @07:08PM (#9282258) Journal
    The author received his doctorate 48 years ago. [ams.org] According to MathSciNet [ams.org] his first paper was in 1963, and his most recent in 1993.

    If it turns out to be true, this will be super-duper-extraordinary - the man is probably in his 70s. G. H. Hardy wrote: "No mathematician should ever allow himself to forget that mathematics, more than any other art or science, is a young man's game". Wiles proved FLT at 40, Perelman of the purported Poincare proof is in his 30s... this is similar-level stuff. The only thing I can think of that even comes close is Fred Galvin in his 50s (?) proving the Dinitz conjecture. [temple.edu]

    You can follow discussions [google.com] on sci.math and fr.sci.maths. Or read about how similar asymptotic proofs about properties of primes failed. [maa.org] Remember, this is arxiv - in the age of electronic preprints, you get many good proofs like Perelman's [arxiv.org] along with almost-proofs like Castro-Mahecha's [soton.ac.uk] and Dunwoody's. [cnn.com]

    • "Hopefully this new paper will have some good cryptographic applications"

      It won't. Sorry. Just like AKS, this is something that's entirely in the realm of the theoretical.

      FP.
      • Now I have something to use at the bars to pick up chicks this weekend! "Hey babe, I don't know how cute you think you are, but I know there are an infinite number of prime twins just waiting to factor this integer." That number theory talk always gets them interested.
        • Irrational numbers are mysterious as a whole, I don't think pi is special in that respect. The prrofs are fascinating though. Prooving incommensurability(sp?) takes some very creative thinking.
          • by Anonymous Coward
            we've known since 1761 [computation.free.fr]
          • Re:Proof (Score:5, Informative)

            by Dominic_Mazzoni (125164) * on Friday May 28 2004, @06:35PM (#9282047) Homepage
            (regarding Pi) What I have to wonder is, how do we know it goes on forever? The answer is we will never know (unless it starts repeating in some big way, which doesn't seem likely), because we can always calculate more digits for it. Thus we can only saw for sure that so far we know it isn't a finite number :-)

            Actually it has been proven that Pi is a transcendental number, which means that it is not the solution to any polynomial equation. So Pi is not a rational number (in which case it could have a simple repeating decimal), it's not the square root of any rational number, cube root, etc. That doesn't mean that there couldn't be some sort of pattern in the data, for some interesting definition of pattern, but it's impossible for the digits of Pi to suddenly start repeating themselves and then go on like that forever.
          • Re:Proof (Score:4, Interesting)

            by JohnFluxx (413620) on Friday May 28 2004, @06:40PM (#9282080)
            It's easy (for a mathematican) to prove that PI is infinite.

            I started trying to write out a proof, but it looks too messy in slashdot :\

            Have a look at something like:

            http://www.lrz-muenchen.de/~hr/numb/pi-irr.html

    • Re:I didn't RTFA (Score:5, Informative)

      by Geoffreyerffoeg (729040) on Friday May 28 2004, @06:22PM (#9281962)
      Because as numbers get higher, there are a lot more numbers below that can be factors, and thus the frequency of prime numbers decreases. E.g., between 1-10 we have 5 prime numbers, but between 1000-1030 there are only 4. This amusing animation [surfeu.fi] that generates prime numbers demonstrates that prime numbers are more rare as you approach infinity (i.e., the program's "prime density" drops).

      Thus it would make sense that the probability of having a twin prime would drop. The question is if it drops to zero or not.

      It can be demonstrated that there are infinite primes, though, by saying that if there were a finite set of primes, you can get a new number by multiplying all the known primes and adding one. This number divided by any of the known primes always gives a remainder of one. Thus it has no prime factors, and is prime. We would then tend to believe there are infinite twin primes, but this is not so easily proven.
    • Re:I didn't RTFA (Score:5, Informative)

      by Dominic_Mazzoni (125164) * on Friday May 28 2004, @06:24PM (#9281971) Homepage
      OK, I'm too lazy to RTFA, but, if there are infinite numbers, why would there not be infinite prime numbers, and infinite prime twins? Are there also not infinite perfect numbers, or ...?

      That's a good question.

      The fact that there are an infinite number of numbers doesn't immediately imply that there are an infinite number of primes, but Euclid figured out how to prove this is true in about 300 BC. It only takes a few sentences to explain it; here's one example [mathforum.org].

      It is definitely not obvious that there are an infinite number of twin primes. It has been an open question for more than a century, and some of the greatest minds in mathematics have worked on it. If this proof is correct, it will be a major result.

      I was trying to think of a good example of something that there is not an infinite number of. Browsing through MathWorld, I found Truncatable Primes [wolfram.com] - there are only 83 of these.

      Can anyone think of any other examples of a type of number that only has a finite number of them, even though at first glance it seems like there might be an infinite number of them?
      • Re:I didn't RTFA (Score:4, Informative)

        by tbjw (760188) on Friday May 28 2004, @09:26PM (#9282849)
        The cases of Fermat Primes, Mersenne Primes (and therefore even perfect numbers) and of Odd Perfect Numbers are still unsolved, to the best of my knowledge.



        Also, of course, there are many well-known diophantine equations (such as n^3 - m^2 -2 = 0) that have finitely many solutions.



        I suppose the most striking example of 'unexpected finiteness' is the orders of sporadic groups (see mathworld.wolfram.com). These are finite groups which have no normal proper subgroups (so their structure is essentially 'irreducible') but they do not fall into any established category of simple group. The largest of these groups are staggeringly huge, but there are only 26. Why this is so is a complete mystery to me.

      • Re:I didn't RTFA (Score:4, Informative)

        by mpsmps (178373) on Friday May 28 2004, @11:46PM (#9283322)
        Can anyone think of any other examples of a type of number that only has a finite number of them, even though at first glance it seems like there might be an infinite number of them?


        Waring's Problem [wolfram.com] provides good examples. For example, the only numbers that cannot be written as a sum of 7 cubes are 15, 22, 23, 50, 114, 167, 175, 186, 212, 231, 238, 239, 303, 364, 420, 428, and 454.

    • by Sigma 7 (266129) on Friday May 28 2004, @08:07PM (#9282518)
      3, 5, 7?
      There is only one set of prime triplets where the numbers are seperated by 2. There are no other triplets because at least one number in that triplet is a multiple of 3. (The numbers being X, X+2, and X+4. Using modular arithmtic to cap the additives would therefore require all numbers of the set X, X+2 and X+1 to not be a multiple of three, which isn't really possible because of how Integer numers work.)

      Or prime siblings that are seperated by numbers other than 2?
      To find an infinite number of prime siblings, you first need to find an appropriate set of numbers. To cut down on processing time, you should note that these numbers are seperated by 6, or a multiple thereof.