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General Solution for Polynomial Equations? 482

An anonymous reader writes "On september 9, several media reported that a young Dutch student found a formula to determine the roots of any polynomial equation. Does this conflict with Abel's proof that such a formula cannot exist? Here is the news item (in Dutch) on his school's homepage." Another reader writes "A Dutch student at the Fontys school of physics has solved a math problem of several centuries old: finding the roots of any polynomial equation. Arxciv copy here. Although an exact solution has been proven impossible for higher orders, this is not the case for numeric solutions."
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General Solution for Polynomial Equations?

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    • Re:The fish (Score:5, Funny)

      by Ctrl-Z ( 28806 ) <tim&timcoleman,com> on Friday September 10, 2004 @08:59AM (#10211495) Homepage Journal
      Is there a math-to-English translator for those of the Slashdot community that can't understand the PDF? Theoretically, I should be able to read it -- I have a degree in mathematics -- but we aren't all so lucky.
    • Re:The fish (Score:4, Funny)

      by Anonymous Coward on Friday September 10, 2004 @09:02AM (#10211519)
      Why did I keep expecting the words "bork bork bork" to come while reaing that?
  • by JoshieCK ( 718463 ) on Friday September 10, 2004 @09:01AM (#10211506) Homepage
    Last quarter's PreCalc class said this was impossible? Now it's possible?
    Dang it, that means I'll have to buy a new math book for this quarter's Calc class, won't I?

    Ah, the world, she is a changin'...
    • Man... I was thinking this was really cool. But now I'll probably have to buy a new book as well =( I think this is just a ploy by "the man" to sell more calc books... bastard.
    • by Xyrus ( 755017 ) on Friday September 10, 2004 @09:21AM (#10211690) Journal
      It's a NUMERIC solution, not an ALGEBRAIC solution.

      Abel's proof showed that polynomials with a degree higher than 4 could not be solved algebraically (i.e through a finite number of additions, subtractions, multiplications, etc.). Abel's proof did no say it was impossible to solve the equations (indeed, numerical solutions to these equations are solved regularly).

      This is similar to how some integral equation solutions cannot be expressed in simple terms. However numerical answers are rather easy to obtain (even easier with a computer) :).

      The method presented is a simpler way to find the roots of polynomial equations numerically by treating it like a power series (x, x^1, x^2,...,x^n) and applying standard differential techniques.

      Pretty cool if you ask me. :)

      ~X~
      • by pjt33 ( 739471 ) on Friday September 10, 2004 @09:50AM (#10211959)
        It's a shame the paper doesn't say why this is better than using Sturm sequences, which work perfectly well.
        • I agree the paper is lacking somewhat in describing why this algorithm is better. I looked into Sturm sequences. It appears that part of the algorithm is relying on a similar principal. The difference seems to come in when trying to converge on the root, which the student is using differential methods.

          But as you pointed out, I'm not sure what the advantage is in doing so. I wouldn't really classify that document as a paper, more like an empirical proof. It is not by any stretch rigorous (for instance you d
        • by Anonymous Coward on Friday September 10, 2004 @10:49AM (#10212611)
          It's a shame the paper doesn't say why this is better than using Sturm sequences

          Less Drang.

      • by slashrogue ( 775436 ) on Friday September 10, 2004 @10:13AM (#10212208)
        I would agree with it being cool if I understood any of what you just said. :\
        • by Austerity Empowers ( 669817 ) on Friday September 10, 2004 @11:04AM (#10212753)
          In the event you weren't joking (I'm sure lots of people don't know what he means), I believe it means that there will never be a magic equation to 4th order polynomials and above like one learned in algebra to the 2nd order polynomial:
          ax^2+bx+c =0
          which is:
          x= (-b +- sqrt(b^2-4ac))/2a
          (aka the quadratic equation)

          Instead you can get VALUES for the roots by using algorithmic approaches, but you cannot come up with a generalized equation like the quadratic equation above.

          If it still doesn't make sense, then it probably doesn't matter, but some lines of engineering require finding roots of high order polynomials. I haven't done it since school, so my whole post may be wrong, but there's your explanation =)
      • I already made a long post explaining the article (if you are really curious look at my recent posts) but I needed to point out here that you forgot radicals in your descriptiong. Even the quadratic isn't solveable in terms of finite additions subtractions, multiplications. Abel's theorem says that you can't solve the general polynomial of degree five or higher using addition, multiplication and taking nth-roots.

        Personally, I am entierly unimpressed with this paper. The numerical method involved looks h
    • Last quarter's PreCalc class said this was impossible?

      Anything is possible at Zombo.com [zombo.com].

  • by Anonymous Coward on Friday September 10, 2004 @09:02AM (#10211514)
    a formula to determine the roots of any polynomial equation. Does this conflict with Abel's proof that such a formula cannot exist?

    Although an exact solution has been proven impossible for higher orders, this is not the case for numeric solutions.


    No conflict here. Saying that an exact solution does not exist is consistent with saying that numeric solutions do exist.

    A numberic solution is a solution that is "close enough", but not exact. Sort of like saying 2.0000000000000001 = 2. They aren't equal, but for many purposes, they are equivalent.
    • No conflict here. Saying that an exact solution does not exist is consistent with saying that numeric solutions do exist.

      Yeah, except that the author of the paper claims an algebraic solution.
  • by StevenHenderson ( 806391 ) <[stevehenderson] [at] [gmail.com]> on Friday September 10, 2004 @09:02AM (#10211517)
    TI-89 + solver/roots function = roots of polynomial
    • by Alwin Henseler ( 640539 ) on Friday September 10, 2004 @09:51AM (#10211971)
      Some may think a good approximation of a calculation problem is "good enough". Too many variables or numbers? Just throw a more powerful calculator at the problem.

      Not so. Exact solutions like the ones provided by mathematical formulas are still useful for a number of reasons:

      • Using an exact formula can provide a shortcut, that enormously reduces the amount of calculation you have to do. It also allows to do some calculations by hand.
      • More important: an exact solution provides insight in the relation between its variables. That's very important from an educational point of view. And by substituting in other formulas, this can also advance the state of the art in other areas of science. A numerical solution, or a progression towards certain values might help you believe there is a certain relation between variables. An exact solution can help you prove such a relation. That is very significant for any sort of theoretical science.
    • by dasmegabyte ( 267018 ) <das@OHNOWHATSTHISdasmegabyte.org> on Friday September 10, 2004 @10:12AM (#10212199) Homepage Journal
      Don't mock the TI-89. That's what they're using to serve this article.
  • by Anonymous Coward on Friday September 10, 2004 @09:02AM (#10211522)
    Without RTFA I can categorically state that it's all Dutch to me...
  • by gowen ( 141411 ) <gwowen@gmail.com> on Friday September 10, 2004 @09:03AM (#10211526) Homepage Journal
    Popular media today reports that someone has done what is well established to be impossible. Now, which one is more likely:
    i) Abel's proof contains a flaw that generations of extremely talented mathematicians have failed to spot in their years and years of teaching it.
    ii) Student mistaken; popular media talking out of arse.

    (Can't read PDF; slashdotted)
    • I'd say it's about 50/50
    • by Chris_Jefferson ( 581445 ) on Friday September 10, 2004 @09:15AM (#10211629) Homepage
      Actually, I'm fairly certain it is:
      iii) Student comes up with interesting (and possibly new, I don't know) result of generating infinate series which converges to root of polynomial. Someone (popular media?) believes that this violates Abel's proof (it doesn't, his proof is for finite representations of the roots).

      This has NOTHING to do with Abel, or Godel, or anyone other related theories, as they do not consider the case of infiniate series.
      • by Gr8Apes ( 679165 ) on Friday September 10, 2004 @09:42AM (#10211882)

        Using series to approximate the solution of differntial equations is taught in class. Heck, go a little further in mathematics and you'll conjure up polynomials functions as the solution to a set of partial differential equations, known as the Galerkin Method [duke.edu]

        So in what way is the above news? (Hint, take a look at the link and what's stated there.)

    • by gr8_phk ( 621180 ) on Friday September 10, 2004 @09:16AM (#10211643)
      iii) Media doesn't understand the difference between an exact solution in radicals and a numeric algorithm. Neither does the public.

      Now I'll RTFA to determine which it really is....

    • i) Abel's proof contains a flaw that generations of extremely talented mathematicians have failed to spot in their years and years of teaching it.

      ii) Student mistaken; popular media talking out of arse.

      iii) Abel's theorem holds ("you cannot solve all polynomial equations by radicals"); student solves all polynomial equations not using radicals but using differential equations and power series; popular media like /. do not understand that this method is known for more than hundred years and that there is no

  • Mirror (Score:5, Informative)

    by avalys ( 221114 ) * on Friday September 10, 2004 @09:06AM (#10211546)
    Apparently some people can't get to the site, which is funny because I'm having no problem, but here is a mirror.

    The Roots of any Polynomial Equation [mit.edu]
    • Re:Mirror (Score:3, Interesting)

      by SydShamino ( 547793 )
      Off-topic, but if you are at MIT, then perhaps your requests are routing through Internet 2? Just a thought. Try tracerouting to the site and see what you get.
  • Its no big deal (Score:5, Informative)

    by moss1956 ( 246946 ) on Friday September 10, 2004 @09:07AM (#10211547)
    The theorem of Abel (or Galois) that is being referred to merely claims that you can't find a general formula built from just the arithmetic operations plus taking nth roots. It has been known for a long time that there is a general formula using elliptic functions.

    The student just used the method of formal power series to solve the equation. This approach dates back at least to Cauchy ~1850 and probably can be found in the works of Euler.
  • From now on I will replace the phrase "It's Greek to me," as in, "I can't understand any of that," with the phrase "It's Dutch to me."

    I will do this whenever possible in honor of this Dutch student's obviously impressive, but absolutely inscrutable (to me) breakthrough.
  • by mikael ( 484 ) on Friday September 10, 2004 @09:07AM (#10211550)
    I'm surprised he didn't include some sample Matlab, Java applet or C code in his paper. It would be useful to have a demonstration that this really works.
  • I am old (Score:2, Interesting)

    by TheVidiot ( 549995 )

    This is yet another reminder of how long it has been since I was in university....

    I can recognized the names of the equations involved, but that's about it...

    In many ways, that illustrates how useful the knowledge has been over the years!
  • by Paster Of Muppets ( 787158 ) on Friday September 10, 2004 @09:10AM (#10211574)

    LISTER: Yeah, the Skutters managed to smuggles something out of the medi-lab for us, y'know that stuff that helps impotent guys put the zest back in their love lives?

    KRYTEN: 'Boing!', the virility enhancement drug!?

    LISTER: That's the stuff, and we've Mickey Finn'd their drinks.

    RIMMER: Within seconds, you're harder than a quadratic equation, and, it doesn't wear off for seven hours.

    KRYTEN: For seven hours those guys are going to be like catapults!

    Red Dwarf, Series 8, Episode 6 [blueyonder.co.uk]

  • by Kohath ( 38547 ) on Friday September 10, 2004 @09:11AM (#10211587)
    The rule of equations (at least in school) is:

    The more complicated the equations for the math problem looks, the more likely the answer is 1.
  • by hankwang ( 413283 ) * on Friday September 10, 2004 @09:12AM (#10211593) Homepage
    I am a phycisist, not a professional mathematician, and I didn't understand all steps in the whole paper. However, the author mentions a series expansion with an infinite number of terms in equation (6), although only the first n terms are ever used in defining the solution. That sounds a bit strange to me. In any case, the exact solution for a third-order equation (n=3) involves lots of cube roots and I don't see those anywhere, which also suggests that it's all about an approximation method.
  • by arnoroefs2000 ( 122990 ) * on Friday September 10, 2004 @09:13AM (#10211604) Homepage
    Check it out... [nyud.net]
  • by D_Nice ( 18143 ) on Friday September 10, 2004 @09:14AM (#10211621) Homepage
    While I was in HS and College, this would have made so much sense to me. Looking at all the work behind it just makes my head hurt now. I think I replaced my math knowledge with coding ability.
  • Easy! (Score:4, Funny)

    by Bluesman ( 104513 ) on Friday September 10, 2004 @09:15AM (#10211625) Homepage
    (1) Let Sa be the set of all possible roots of polynomial equations.

    (2) From [1], we have determined that the correct roots, a1...an, exist in Sa.

    (3) Let the set Sb be the set that contains only a1...an.

    (4) The intersection of sets Sa and Sb will thus be the roots of the polynomial equation.

    Therfore, we derive the formula:

    Sa ^ Sb = roots
  • europe (Score:5, Funny)

    by nnnneedles ( 216864 ) on Friday September 10, 2004 @09:20AM (#10211675)
    The present:
    european academic finds solution to very hard problem.

    2 years later:
    a) americans find way of turning said solution into entertainment technology and make billions of dollars.b) European academic still unemployed and eating pasta all week.

    We need more GREED in europe.. :/

  • by wondafucka ( 621502 ) on Friday September 10, 2004 @09:21AM (#10211695) Homepage Journal
    I mean, come on. A Dutch student?
  • by 808140 ( 808140 ) on Friday September 10, 2004 @09:28AM (#10211753)
    The article in question is slashdotted, but my guess is either that this is media sensationalism, or the writeup is claiming something different from the student -- it seems like perhaps a new way to numerically approximate polynomial roots has been discovered.

    However, from what I remember, Abel's theorem was proven using Galois Groups and Field extensions. This implies that what it actually proves is that analytical solutions using a particular set of functions -- in particular, the field operations (addition, subtraction, multiplication, division by non-zero) extended to include radicals (square, cubic, etc roots), composed in any way possible (as in a ruler and compass construction proof) cannot possibly generate an analytical formula depicting the solution for polynomials of order greater than 4.

    Does this mean that an analytical formula using other functions is impossible? Not at all. Trivially, I will define a function called, say, omega, which, given a n-dimensional complex vector, gives a solution to one of the roots of the function a_n * x^n + a_(n-1) * x^(n-1) + ... + a_0 where a_n are the elements of said vector. Then, by repeated application of omega and polynomial long division, I have an analytical solution to any polynomial, of any order, in complex space.

    Clearly, this solution is analytical in the sense that it a) provides an exact solution and b) is algebraic in nature. However, it isn't useful, because it depends on a function (omega) which cannot itself be defined analytically in terms of other functions (or at least, not ones we know how to compute).

    The reason Abel's proof is so important is because it deals with the 4 fundamental operations that polynomials themselves use (the field ops) and adds radicals, which are inverse ops to the building blocks of polynomials themselves. So it essentially says, we cannot use the functions that we constructed the polynomial with to solve it.

    Now, my omega function may seem a little bit contrived to non-math types, but actually a large number of functions are arbitrarily defined this way. Logarithms are a good simple example. An analytical formula for the likes of log n wouldn't be possible either, and yet we study logarithms without having an express analytical means of calculating them.

    What you should ask yourself is, what does analytical mean, anyway? It really isn't useful (or correct) to say that no analytical solution exists unless you explicitly restrict what particular set of 'basic' functions/operators the analytical solution can contain. In Abel's case (and it's a beautiful proof, by the way) he uses the field operators plus radicals. But what if you added logarithms into the mix? Exponential functions?

    It's impossible to say. If you don't restrict your base, you open yourself up to the attack that I just used with the omega function (which certainly exists, after all, I just defined it.)
  • No closed formula (Score:5, Insightful)

    by MoobY ( 207480 ) <anthonyNO@SPAMliekens.net> on Friday September 10, 2004 @09:32AM (#10211794) Homepage
    Note that the student's result is not a closed formula, and is thus not in conflict with Abel's proof. The system uses convergence (and thus, reuires an infinite number of operations) to find the correct roots.
  • by Ann Coulter ( 614889 ) on Friday September 10, 2004 @09:41AM (#10211865)
    I used hypergeometric functions to solve the equation

    a x^b + c x^d + e x^f = 0

    where the exponents are integers and the coefficients can be complex. I tried to generalize it for complex exponents but I quit after a while. Google should provide some preliminary information on using hypergeometric functions to solve the quintic

    a x^5 + b x^c + e = 0

    where c is less than 5 and greater than zero.

    This is an analytic solution to the general trinomial that I found empirically (without proof). If one wants to solve to solve the quartnomial then two dimensional structures, quintnomials need 3 dimensional structures. This was computationally taxing on me and my computer so I didn't even consider the quartnomial equations.

    By the way, I have implemented a Jenkins-Traub algorithm not so long ago that gives numerical approximations to general polynomial roots. It is fast and well known.
  • From a seasoned math professor's reading of it: "It looks like a mess to me.
    I don't know what his point is. He says its a "method of solving the roots"
    of a polynomial. Well, we already have very fine methods for doing that,
    interval Newton methods for instance. Using circular disk arithmetic in the
    complex plane we can find all the complex roots as well.
    There is no need whatever to make things more complicated such as going to
    differential equations. That is unneccessary. Root finding is an algebraic
    problem."
    • more quotes from the professor: "The "range" software of Oliver Aberth (that I have on our computer) can find
      all the roots, real and complex, of any polynomial to whatever accuracy you
      specify. Of course the more you ask for, the longer it may take, but it's
      pretty fast for ten places for polynomials of degree say ten or so.
      His book "Precise Numerical Methods Using C++" describes the methods used in
      his range software."

      Those are guaranteed solutions, too, not just "i think it's pretty close, but there's no way to prove it."

      They also have guaranteed solvers for nonlinear (and/or partial) DE's... this kid is about 50 years too late.
  • by high na ( 812303 ) on Friday September 10, 2004 @09:53AM (#10211994)
    In this poster, they discuss this topic precisely, including Abel's theorem. One of the readers was correct: although Abel proved impossibility of solution for polynomials higher than degree 5 IN TERMS OF ROOTS AND OTHER ALGEBRAIC ENTITIES, there is nothing ruling out a solution in terms of, say, hypergeometrics. This is precisely what they do, and there's a nice development of this using power series. So, although I didn't get to read the PDF, it seems from the posts here that this is what the student did. Thus, no big deal. That said, I salute the student for figuring this out on his own, and he shouldn't be discouraged by discovering something that is not new.
  • by coult ( 200316 ) on Friday September 10, 2004 @10:18AM (#10212248)
    From what I can tell, it appears to be a method for transforming a polynomial into a differential equation some of whose solutions are roots of the polynomial. From that point I suppose one could use numerical methods for ODE's to find those solutions.

    People here have been commenting that Newton's method works just fine for finding roots of polynomials. But, convergence can be quite slow, especially for unidentified multiple roots though, and for highly clustered roots you can run into conditioning problems.

    The paper makes no mention of actual numerical algorithms (in particular no discussion of convergence rates or guarantees for solving the ODE numerically) so it is hard to say whether the result is actually useful or just a bunch of manipulation of symbols on paper.
  • Translation (Score:3, Informative)

    by curtvdh ( 738461 ) on Friday September 10, 2004 @10:24AM (#10212312)

    Disclaimer: it has been years since I've spoken Dutch. What follows hsould be taken with a fairly large grain of salt...

    Fontys student develops important mathematical discovery

    While most students languished on the beaches this Summer, Fontys student Geert-Jan Uytdewilligen discovered the solution to one of the oldest mathematical problems. He proved an inportant step in - wait for it - the classification of the zero-points of polynomials of any order.

    This problem was already known to the ancient Egyptians. During the Renaissance, a clearer understaning of (the problem) existed, and one 19th century scientist published (a paper) on his findings that stated the problem could not be solved. But Geert-Jan Uytdewilligen, a fourth-year student at Fontys High-school of Applied Science finally shed light on the complex problem. He discovered a formula for the classification of the zero-points of any order. Mathematical proofs have thus far not come from the sixth grade.

    Difficult Puzzles

    Ever since his youth, Geert-Jan Uytdewilligen was obsessed with the solution of difficult puzzles. 'I always feel at home in abstract thought', he says, 'In elementary school, I was very good at arithmetic, and therefore in my future studies, I stuck to mathematics. At one particular point in (my) mathemetics lesson, (we) handled the parabola. From that moment, I became interested in the pure algebraic problems that flowed from that. In particular, the higher grade comparison of the zero-points intruiged me, since mathematicians had been searching for a solution to the problem for ages. This was a challenge for me, to solve the problem which is purely theoretical. I had a slight practical advantage, because one can usually fill in the numbers(?) with a computer. The problem is then solved in this manner.'

    Polynomials

    Geert-jan designed mathematical formulae that were previously regarded as not-undestandable by the layperson. Perhaps you might recognize this formula: a[n]*x^n+a[n-1]*x^(n-1)+..+a1*x+a0=0. 'This is the general form of a regular polynomial', he says. Regular polynomials are a combination of increasing powers and multiplication. If you solve for x in this formula, then you get the zero-points of the polynomial. Polynomial solutions up to the sixth order are already known. I found a formula to find the zero-points of a polynomial of any order!'

    Publication

    Geert-Jan's discovery first saw light of day in the magazine Science Guide, and generated a lot of publicity. This was the reward of two years of hard work. Geert-Jan: 'You don't expect such a vague starting-point to result in such a hit. This is strange, considering the amount of technical jargon, which make the theory hard to follow. But at the same time, the pieces of the puzzle began to come together. Yes, I had the Eureka-moment! But I remained a freely sober person, and held myself together. I didn't allow my studies to suffer because of my hobby.'

  • Looks flawed (Score:5, Informative)

    by hanwen ( 8589 ) on Friday September 10, 2004 @10:54AM (#10212653) Homepage Journal
    Looks flawed to me. He performs a sensitivity analysis in the constant of the polynomial (which he calls "s"). It remains unclear why. After a convoluted sequence of operations, he derives a power series for x as function of s , and proves convergence by requiring |s| smaller than 1.

    Finally, he puts back a_0 into s, but conveniently forgets the case that a_0 is bigger than 1.

    Also, it is not clear whether this is in the complex plane or not. For example, for finding real roots of real polynomials, you could use Sturm Sequences. There's even sample code in graphics Gems IV (IIRC).

    In any case, the student was studying at the "hogeschool" which roughly translates to "higher professional education", a school which doesn't teach mathematics, and whose level which significantly lower than Dutch the MSc., BSc. or engineering degree.

    Han-Wen

    (yes, I am a mathematician)

    • Professional (Score:3, Interesting)

      by thrill12 ( 711899 ) *
      Not a mathematician here, but just a fellow dutchman who likes to add that even though the student in question isn't studying at a university, that doesn't simply mean he couldn't have come up with a nice idea.
      Besides, at the "Hogeschool" there is teaching of mathematics, just not in the same way as at an university: It is much more "practical" - ie. without going through all the 'proving-stuff' - and the level is generally lower than at a university. But the technical studies still provide an adequate leve
    • Re:Looks flawed (Score:4, Informative)

      by Anonymous Coward on Friday September 10, 2004 @11:44AM (#10213212)
      Finally, he puts back a_0 into s, but conveniently forgets the case that a_0 is bigger than 1.

      Except he doesn't forget this. He tells you to divide the polynomial by a constant to make it so. Since you're a "mathematician" let me help you visualize this difficult step:

      18x^6 - 12x^3 + 3 = 0 ... divide by 6
      3x^6 - 2x^3 + 1/2 = 0

      Gee, a_0 is less than 1 now and the roots are the same. Huh, I wonder how that happened? In actuallity he tells you to divide by a larger number such that all of the coefficients are fractions, but you get the picture.

      • Re:Looks flawed (Score:4, Insightful)

        by ninja0 ( 764532 ) on Friday September 10, 2004 @12:13PM (#10213493)
        Nope, grandparent was right. You can't just divide and expect convergence to suddenly occur. I believe the leading coefficient is assumed to be 1 for the result he's using. IAA math major.
        • Re:Looks flawed (Score:3, Informative)

          by Anonymous Coward

          Read the paper. There is no such assumption that a_n=1. (Why else have a_n in the numerator of equation 5 if it's always 1?) He is quite explict about dividing by "(more than) the maximum of the absolute values of the coefficients". Dividing by any non-zero constant (even complex) does not change the roots of the polynomial at all.

          Assuming his formula are correct for the expansion coefficients, the series is guaranteed to converge once you perform the recommended normalization. The grandparent is wrong, a

    • Re:Looks flawed (Score:3, Insightful)

      by oGMo ( 379 )

      (yes, I am a mathematician)

      Well then,

      After a convoluted sequence of operations,

      Sounds like precise mathematical terminology and understanding of the operations.

      In any case, the student was studying at the "hogeschool" which roughly translates to "higher professional education", a school which doesn't teach mathematics, and whose level which significantly lower than Dutch the MSc., BSc. or engineering degree.

      Typical academic arrogance. Letters after your name do not make your more corr

      • Re:Looks flawed (Score:3, Interesting)

        by hanwen ( 8589 )
        You may be right in this case---but show where the mathematical errors are, don't point at credentials.

        The problem is that it is not "mathematics," in the sense that he doesn't write a logical sequence of formally specified lemmas, proofs or conclusions. It is not clear what the author is doing, so it is also not possible to pinpoint exactly where the errors are.

      • Re:Looks flawed (Score:3, Insightful)

        by Sage Gaspar ( 688563 )
        This kid is in what I'm guessing is the equivalent of a really good technical high school, so he deserves praise for just being at the level of messing around with this kind of stuff, let alone attempting to publish a paper. I'm sure some of his paper is lost in translation, but, commenting on the paper itself, it would never get accepted into a reputable journal for publication.

        First, he never gives any clear indication whatsoever of what he intends to prove that his method will do. What does it mean to p
  • by sixpaw ( 648825 ) on Friday September 10, 2004 @11:03AM (#10212738)
    ...as others pointed out, this is simply the method of power series, and it's even a pretty clumsy way of getting at that power series (why generate a differential equation when you can plug power series coefficients into the original equation itself?)

    What I'm surprised at, though, is that nobody's pointed out the most obvious problems with this scheme:
    1. Your polynomial has (up to) n roots; this approach converges, maybe, to one of them. Which one do you get, and how do you get the others?
    2. For that matter, some chunk of those n roots may be complex; but all the maths in his article are real. How do you solve, say, x^6+1 = 0?
    The change in radius of convergence at the end of his post is a little dicey too, at least as I'm reading it, but I could be misreading. Still, I'm frankly stunned. Worthy of a press release? If I'd turned this in as a school assignment it wouldn't even have been worth an A!
  • by logicnazi ( 169418 ) <gerdesNO@SPAMinvariant.org> on Friday September 10, 2004 @01:15PM (#10214097) Homepage
    Alright, whoever wrote the article seems very confused about mathematics and abel's theorem in particular. I'm not actually an algebraist myself but I am in mathematical logician so I can comment a bit about impossibility results.

    Abel's theorem merely says you can not solve the general quintic (5th degree) or higher in terms of radicals. That is entierly in terms of multiplication, addition, and taking nth roots. If we don't put that restriction about radicals the solution is trivial. Let x be such that P(x)=0 is one obvious solution.

    Going through this again the write up is *entierly wrong*. It is completly possible to give an exact solution for the general polynomial (I just did in the paragraph above). Furthermore this distinction between exact and numerical solutions which is made so much of by our high school and college teachers is really illusionary. Writing a solution in terms of sin(3) isn't an exact value, we just have a good algorithm to approximate sin. Really what we mean when we talk about exact solutions is solvable in elementary functions, which is nothing but a certain commonly used set of functions for which we have good approximations. Unfortunatly, we still insist on students 'solving' differntial equations rather than just finding some quickly converging numerical solution even though at a deep level these are not differnt.

    Now since abel's theorem there has been considerable research on other ways to solve polynomial equations. For instance one big result was that a certain degree of polynomials could be solved in a terms of continous two place function. Possibly this result in question is another result like this one but I imagine it is much less significant. For one I'm not entierly convinced he is correct, nor novel. (Don't make the mistake of assuming if he is right he has given a continous solution of any polynomial..it isn't clear his solution is continous in the coefficents).
  • by Performer Guy ( 69820 ) on Friday September 10, 2004 @06:00PM (#10217126)
    Proofs cannot be contradicted that's the point. That's why it's called a proof.
  • by dido ( 9125 ) <dido&imperium,ph> on Saturday September 11, 2004 @09:23AM (#10220331)

    The method presented in the paper looks a lot like James Cockle and Robert Harley's differential resolvent, which was new in 1862. This page [wolfram.com] gives an overview of some of the known methods for solving quintic and higher degree equations. Apparently, about twenty years ago Hiroshi Umemura [nagoya-u.ac.jp] found a general analytical solution for a polynomial equation of arbitrarily high degree involving Siegel modular forms, which are generalizations of the elliptic modular functions Charles Hermite used in 1858 as a solution to the quintic. Note: these don't violate Abel's Impossibility Theorem as they are not solutions in radicals.

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