All functions g:N-->N which have a single-fold Diophantine representation are dominated by a limit-computable function f:N\{0}-->N which is implemented in MuPAD and whose computability is an open problem

摘要

Let E_n={x_k=1, x_i+x_j=x_k, x_i \cdot x_j=x_k: i,j,k \in {1,...,n}}. For anyinteger n \geq 2214, we define a system T \subseteq E_n which has a uniqueinteger solution (a_1,...,a_n). We prove that the numbers a_1,...,a_n arepositive and max(a_1,...,a_n)>2^(2^n). For a positive integer n, let f(n)denote the smallest non-negative integer b such that for each system S\subseteq E_n with a unique solution in non-negative integers x_1,...,x_n, thissolution belongs to [0,b]^n. We prove that if a function g:N-->N has asingle-fold Diophantine representation, then f dominates g. We present a MuPADcode which takes as input a positive integer n, performs an infinite loop,returns a non-negative integer on each iteration, and returns f(n) on eachsufficiently high iteration.