On the spatial mean of the Poincare cycle

dc.creatorBaez-Duarte, Luis
dc.date2005-05-28
dc.date.accessioned2026-07-07T05:20:20Z
dc.date.available2026-07-07T05:20:20Z
dc.descriptionLet $X$ be a measure space and $T:X\to X$ a measurable transformation. For any measurable $E\subseteq X$ and $x\in E$, the possibly infinite return time is $n_E(x):=\inf\{n>0: T^n x\in E\}$. If $T$ is an ergodic tranformation of the probability space $X$, and $μ(E)>0$, then a theorem of M. Kac states that $\int_E n_E dμ=1$. We generalize this to any invertible measure preserving transformation $T$ on a finite measure space $X$, by proving independently, and nearly trivially that for any measurable $E\subseteq X$ one has $\int_E n_E dμ=μ(I_E)$, where $I_E$ is the smallest invariant set containing $E$. In particular this also provides a simpler proof of Poincaré's recurrence theorem.
dc.description2 pages, Translation into English of a paper by the author generalizing Kac's theorem on the spatial mean of the Poincare cycle. Of possible pedagogical value
dc.identifierhttps://arxiv.org/abs/math/0505625
dc.identifierhttp://arxiv.org/abs/math/0505625
dc.identifierBull. Venezuela Acad. Sci. 1964
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/75346
dc.subjectProbability
dc.titleOn the spatial mean of the Poincare cycle
dc.typetext

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