Skolem Meets Bateman-Horn
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The Skolem Problem asks to determine whether a given integer linear recurrence sequence has a zero term. This problem arises across a wide range of topics in computer science, including loop termination, (weighted) automata theory, and the analysis of linear dynamical systems, amongst many others. Decidability of the Skolem Problem is notoriously open. The state of the art is a decision procedure for recurrences of order at most 4: an advance achieved some 40 years ago based on Baker's theorem on linear forms in logarithms of algebraic numbers. Recently, a new approach to the Skolem Problem was initiated via the notion of a Universal Skolem Set: a set 𝐒 of positive integers such that it is decidable whether a given non-degenerate linear recurrence sequence has a zero in 𝐒. Clearly, proving decidability of the Skolem Problem is equivalent to showing that ℕ is a Universal Skolem Set. The main contribution of the present paper is to exhibit a Universal Skolem Set of positive density that moreover has density one subject to the Bateman-Horn conjecture in number theory. The latter is a central unifying hypothesis concerning the frequency of prime numbers among the values of systems of polynomials, and provides a far-reaching generalisation of many classical results and conjectures on the distribution of primes.
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