The Skolem Problem in rings of positive characteristic
Abstract
We show that the Skolem Problem is decidable in finitely generated commutative rings of positive characteristic. More precisely, we show that there exists an algorithm which, given a finite presentation of a (unitary) commutative ring of characteristic , and a linear recurrence sequence , determines whether contains a zero term. Our proof is based on two recent results: Dong and Shafrir (2026) on the solution set of S-unit equations over -torsion modules, and Karimov, Luca, Nieuwveld, Ouaknine, and Worrell (2025) on solving linear equations over powers of two multiplicatively independent numbers. Our result implies, moreover, that the zero set of a linear recurrence sequence over a ring of characteristic is effectively a finite union of -normal sets in the sense of Derksen (2007).
Keywords
Cite
@article{arxiv.2510.27603,
title = {The Skolem Problem in rings of positive characteristic},
author = {Ruiwen Dong and Doron Shafrir},
journal= {arXiv preprint arXiv:2510.27603},
year = {2026}
}
Comments
Corrected a small error in Lemma 3.2