(New page: =The Erdos-Woods Problem= ==Setup== '''Fundamental Theorem of Arithmetic''': Every integer $n >1$ can be expressed uniquely as a product $$n = p_1^{e_1} \cdots p_k^{e_k}$$ where the $p_i$...)
 
 
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=The Erdos-Woods Problem=
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= The Erdös-Woods Problem=
  
==Setup==
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The Erdös-Woods problem is a surprisingly far reaching question about integers. I has implications for mathematical logic, [[ABC triples]], [[elliptic curves]], and can be generalized to (affine) [[schemes]]. This generalization provides links between number theory and Nevanlinna's value distribution theory in complex analysis. Connections between Nevanlinna theory and number theory have already been emphasized by Lang and Vojta in connections with Roth's theorem.  
'''Fundamental Theorem of Arithmetic''': Every integer $n >1$ can be expressed uniquely as a product
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$$n = p_1^{e_1} \cdots p_k^{e_k}$$
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where the $p_i$ are prime number satisfying $p_i < p_j$ if $i < j$ and the $e_i$ are positive integers.
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'''Defintion (Radical)''': The ''radical'' of an integer $n$, denoted $\text{rad}(n)$, is defined simply as the product of all prime divisors of $n$. That is, if $n = p_1^{e_1} \cdots p_k^{e_k}$ then $\text{rad}(n) = p_1 \cdots p_k.$
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This completely independent connection suggests that the ABC conjecture could stated for the ring of entire functions. I seems plausible that it could even be proven by one of our friendly neighborhood Nevanlinna theorists.  
  
'''Remark''': The only reasonable thing to do is to define $\text{rad}(1) = 1.$
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'''UPDATE:''' Apparently ABC conjecture has already been proven for the field of meromorphic functions. This was the topic of a recent Séminaire Bourbaki, documented [http://arxiv.org/pdf/0811.3153v1 here].
  
==The Evil Wizard==
 
  
Suppose you are confronted by an evil wizard who presents you with the following challenge:
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= Algorithm =
  
"'''I'm going to pick a positive integer $n > 1$ and then I shall tell you the radical of each integer from $n$ to $n+k$. Then you must tell me what $n$ is.'''"
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One way to think about the Erdös-Woods problem for integers is as follows. You are confronted by an Evil Wizard who tells you that he is thinking of an integer $n$. He will tell you the primes dividing $n$, $n+1$, and $n+2$ respectively. You are asked to determine $n$. Given $V(n)$ and $V(n+1)$ we can prove, by invoking a theorem of Shafarevich, that there are only finitely many possible values of $n$.  
  
For which $k$ should you accept this challenge? Discuss...
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A reasonable computational task is to compute this finite set. This involves computing the set of all elliptic curves with full two-torsion with good reduction outside a finite set of primes. Noam Elkies has suggested that the best way to do this might be to compute the set of all possible [[Lambda Invariants]] by solving an [[S-Unit Equation]]. These equations can be solved using Baker's method of [[Linear Forms in Logarithms]].

Latest revision as of 15:48, 5 August 2010

The Erdös-Woods Problem

The Erdös-Woods problem is a surprisingly far reaching question about integers. I has implications for mathematical logic, ABC triples, elliptic curves, and can be generalized to (affine) schemes. This generalization provides links between number theory and Nevanlinna's value distribution theory in complex analysis. Connections between Nevanlinna theory and number theory have already been emphasized by Lang and Vojta in connections with Roth's theorem.

This completely independent connection suggests that the ABC conjecture could stated for the ring of entire functions. I seems plausible that it could even be proven by one of our friendly neighborhood Nevanlinna theorists.

UPDATE: Apparently ABC conjecture has already been proven for the field of meromorphic functions. This was the topic of a recent Séminaire Bourbaki, documented here.


Algorithm

One way to think about the Erdös-Woods problem for integers is as follows. You are confronted by an Evil Wizard who tells you that he is thinking of an integer $n$. He will tell you the primes dividing $n$, $n+1$, and $n+2$ respectively. You are asked to determine $n$. Given $V(n)$ and $V(n+1)$ we can prove, by invoking a theorem of Shafarevich, that there are only finitely many possible values of $n$.

A reasonable computational task is to compute this finite set. This involves computing the set of all elliptic curves with full two-torsion with good reduction outside a finite set of primes. Noam Elkies has suggested that the best way to do this might be to compute the set of all possible Lambda Invariants by solving an S-Unit Equation. These equations can be solved using Baker's method of Linear Forms in Logarithms.

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