[HN Gopher] Dear Julia, Dear Yuri: A mathematical correspondence...
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       Dear Julia, Dear Yuri: A mathematical correspondence (2022)
        
       Author : georgecmu
       Score  : 88 points
       Date   : 2024-07-03 01:55 UTC (21 hours ago)
        
 (HTM) web link (celebratio.org)
 (TXT) w3m dump (celebratio.org)
        
       | quibono wrote:
       | Gregory Chudnovsky is one of the Chudnovsky brothers responsible
       | for the Chudnovsky algorithm for calculating digits of pi.
        
         | trallnag wrote:
         | Makes me proud to be a chud myself
        
       | linguaz wrote:
       | Such a wonderful piece. I'd not heard of Julia Robinson or Yuri
       | Matiyasevich...what a touching story of two people forming a
       | friendship across time, place and culture.
       | 
       | > Julia thought of mathematicians "as forming a nation of our own
       | without distinctions of geographical origins, race, creed, sex,
       | age, or even time (the mathematicians of the past and you of the
       | future are our colleagues too) -- all dedicated to the most
       | beautiful of the arts and sciences."
       | 
       | The mathematics is way over my head, but I find this inspiring &
       | would love to see how we might discover/co-create realms beyond
       | such distinctions in other endeavors.
        
         | Cacti wrote:
         | gregory chaitin has an accessible version of the math, if
         | you're interested. he builds a LISP with it.
        
           | linguaz wrote:
           | Thanks for the pointer to Chaitin, his writing seems
           | approachable:
           | 
           | https://link.springer.com/chapter/10.1007/978-1-4471-0307-3_.
           | ..
           | 
           | https://inference-review.com/article/doing-mathematics-
           | diffe...
           | 
           | > he builds a LISP with it
           | 
           | cool, just found these:
           | 
           | The Limits of Mathematics---Tutorial Version :
           | https://arxiv.org/abs/chao-dyn/9509010
           | 
           | An implementation of his Lisp, written to explore the above
           | Tutorial : https://github.com/poppingtonic/chaitin-ait
        
         | mpalmer wrote:
         | I liked this quote too, though I wonder if it's not more out of
         | necessity and the special nature of math than anything else.
         | 
         | Mathematicians speak languages non-math people can't grasp, so
         | they gravitate toward and connect to one another.
         | 
         | Math simply doesn't advance without promiscuous sharing of
         | ideas. Soviet censors notwithstanding, there's certainly a
         | reason correspondence like this was permitted even during the
         | Cold War.
         | 
         | You could say that the above is true of other sciences, but I
         | imagine falsification of results in math is extremely difficult
         | or just impossible. So math is mostly immune (I suggest) to the
         | politics and protectionism that inevitably emerges around fuzzy
         | and controversial scientific disciplines.
         | 
         | Just look at the good faith Julia has in her treatment of
         | Chudnovsky's work. Even the skepticism is respectful.
        
           | linguaz wrote:
           | > I imagine falsification of results in math is extremely
           | difficult or just impossible.
           | 
           | Another quote I like from this piece: "No one can be a
           | charlatan mathematician for long".
           | 
           | If only that were true in certain other domains.
        
       | pierrebai wrote:
       | I'm utterly confused by the description of the solution of
       | Hilbert's 10th problem.
       | 
       | On one hand, the article claims that Diophantine equations are
       | polynomials. On the other hand, it claims that when JR is true, a
       | Diophantine equations grows faster than a polynomial.
       | 
       | How can a polynomial grow faster than polynomial? That seems like
       | a contradiction to me.
        
         | isotropy wrote:
         | Yeah, this is a little bit subtle. Please ignore the lack of
         | rigor below, but this is my understanding: They aren't looking
         | at a particular polynomial like 4x + 3y = 2. That has a
         | solution x=2, y=-2, but they don't really care about the exact
         | value for (x, y), just that it's integers. They're more
         | interested in the parameters: (4, 3, 2), and in general Ax + By
         | = C. If you like, it's almost like hyper parameter tuning: what
         | are the parameter settings for (A, B, C) where I can get this
         | shape of equation to "work", e.g. give me acceptable x and y? A
         | "Diophantine set" is a family of parameters that all work. It
         | turns out you can think of "parameters of a given shape of
         | Diophantine equation" as an exotic programming paradigm.
         | 
         | Fermat: x^N + y^N = z^N. The Diophantine set only has the
         | number N=2, because Fermat's Last Theorem tells us that no
         | other possible N will work if x, y, z have to be integers. This
         | is just a finite set.
         | 
         | Other polynomial expressions work with an infinite number of
         | parameter settings: Pell's equation is x^2 - N*y^2 = 1. In this
         | case, every N that is not a square will work. This is an
         | infinite set.
         | 
         | Because a lot of the parameter sets are infinite like this, the
         | size of the parameter set are instead measured using big-O
         | notation. For Fermat's Last Theorem, {N=2} is constant, so
         | big-O(1). For Pell's equation, {N not a square} is O(N). For
         | other Diophantine expressions, the parameter settings are
         | O(N^2), or O(2^N), or any other growth function you want that's
         | achievable with Turing machines.
         | 
         | And this is the essence of what MRDP proved. Robinson, Davis,
         | Putnam, and Matiyasevich over several papers proved that if you
         | could encode a set that grew roughly like O(2^N), you also
         | could encode any other computable set in the parameters.
         | Approximately, demonstrating an exponentially-fast-growing
         | family of parameters for some specific Diophantine problem was
         | enough for Diophantine problems as a whole to be Turing
         | complete. Matiyasevich's clinching discovery was a concrete
         | example using the Fibonacci numbers.
        
           | isotropy wrote:
           | In fact, according to the Esolang Wiki
           | [https://esolangs.org/wiki/List_of_ideas#Mathematics] ,
           | Gregory Chaitin apparently has built a Diophantine equation
           | whose parameters encode an entire Lisp interpreter.
        
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