{ "id": "2202.07344", "version": "v1", "published": "2022-02-15T12:07:12.000Z", "updated": "2022-02-15T12:07:12.000Z", "title": "A strong Borel--Cantelli lemma for recurrence", "authors": [ "Tomas Persson" ], "comment": "14 pages, 0 figures", "categories": [ "math.DS" ], "abstract": "Consider a mixing dynamical systems $([0,1], T, \\mu)$, for instance a piecewise expanding interval map with a Gibbs measure $\\mu$. Given a non-summable sequence $(m_k)$ of non-negative numbers, one may define $r_k (x)$ such that $\\mu (B(x, r_k(x)) = m_k$. It is proved that for almost all $x$, the number of $k \\leq n$ such that $T^k (x) \\in B_k (x)$ is approximately equal to $m_1 + \\ldots + m_n$. This is a sort of strong Borel--Cantelli lemma for recurrence. A consequence is that \\[ \\lim_{r \\to 0} \\frac{\\log \\tau_{B(x,r)} (x)}{- \\log \\mu (B (x,r))} = 1 \\] for almost every $x$, where $\\tau$ is the return time.", "revisions": [ { "version": "v1", "updated": "2022-02-15T12:07:12.000Z" } ], "analyses": { "subjects": [ "37E05", "37A05", "37B20" ], "keywords": [ "strong borel-cantelli lemma", "recurrence", "return time", "gibbs measure", "piecewise expanding interval map" ], "note": { "typesetting": "TeX", "pages": 14, "language": "en", "license": "arXiv", "status": "editable" } } }