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arXiv · 2609.12402

Effective recurrence for computable measure-preserving transformations

Joey Veltri
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Abstract

We prove several necessary and sufficient conditions under which a point satisfies the Poincaré Recurrence Theorem for all computable (ergodic) measure-preserving transformations and all sets of a particular complexity. The necessary conditions are obtained by constructing specific measure-preserving transformations which violate recurrence. While some of these conditions pertain to standard notions of algorithmic randomness, others involve new notions of genericity developed in the context of a computable probability space, which we call $Π^0_n$-genericity and quasi-$Π^0_n$-genericity. We also provide conditions under which points recur at a positive frequency in sets containing them, regarding both simple and multiple recurrence.

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Joey Veltri. 2026-09-11. Effective recurrence for computable measure-preserving transformations. https://arxiv.org/abs/2609.12402

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