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This paper is motivated by the study of probability measure-preserving (pmp) actions of free groups using continuous model theory. Such an action is treated as a metric structure that consists of the measure algebra of the probability…

Logic · Mathematics 2023-11-08 Alexander Berenstein , C. Ward Henson , Tomás Ibarlucía

In this paper we study ergodic $\mathbb{Z}^r$-actions and investigate expansion properties along cyclic subgroups. We show that under some spectral conditions there are always directions which expand significantly a given measurable set…

Dynamical Systems · Mathematics 2024-12-11 Michael Björklund , Alexander Fish

A measure preserving action of a countably infinite group \Gamma is called totally ergodic if every infinite subgroup of \Gamma acts ergodically. For example, all mixing and mildly mixing actions are totally ergodic. This note shows that if…

Dynamical Systems · Mathematics 2012-08-06 Robin Tucker-Drob

In this paper, we establish that, for statistically convex-cocompact actions, contracting elements are exponentially generic in counting measure. Among others, the following exponential genericity results are obtained as corollaries for the…

Group Theory · Mathematics 2017-07-20 Wenyuan Yang

A {\it uniformly $p$-to-one endomorphism} is a measure-preserving map with entropy log $p$ which is almost everywhere $p$-to-one and for which the conditional expectation of each preimage is precisely $1/p$. The {\it standard} example of…

Dynamical Systems · Mathematics 2007-05-23 Christopher Hoffman , Daniel Rudolph

The theory of ergodic optimization for distance-expanding maps is extended to Gauss's continued fraction map. Since the set of invariant probability measures is not weak$^*$ closed, we establish a characterisation of the closure of this…

Dynamical Systems · Mathematics 2025-12-29 Yinying Huang , Oliver Jenkinson , Zhiqiang Li

This work addresses the existence of transitive extensions of certain infinite permutation groups which arise as the automorphism groups of model-theoretic structures which are generic in the Fra\"iss\'e sense. The study of transitive…

Logic · Mathematics 2026-04-15 Felipe Estrada

We show that a class of ergodic transformations on a probability measure space $(X,\mu)$ extends to a representation of $\mathcal{B}(L^2(X,\mu))$ that is both implemented by a Cuntz family and ergodic. This class contains several known…

Operator Algebras · Mathematics 2018-08-17 Evgenios T. A. Kakariadis , Justin R. Peters

We consider continuous maps of the interval which preserve the Lebesgue measure. Except for the identity map or $1 - \id$ all such maps have topological entropy at least $\log2/2$ and generically they have infinite topological entropy. In…

Dynamical Systems · Mathematics 2026-02-06 Jozef Bobok , Jernej Činč , Piotr Oprocha , Serge Troubetzkoy

Symbolic dynamical theory plays an important role in the research of amenability with a countable group. Motivated by the deep results of Dougall and Sharp, we study the group extensions for topologically mixing random shifts of finite…

Dynamical Systems · Mathematics 2024-03-21 Kexiang Yang , Ercai Chen , Zijie Lin , Xiaoyao Zhou

Let S_1 and S_2 be ergodic extensions of finite measure preserving transformations T_1 and T_2, where the extensions are by rotations of a compact group G. Then there is an N-valued function k, measurable with respect to the factor T_1, so…

Dynamical Systems · Mathematics 2011-12-20 Andrey Babichev , Adam Fieldsteel

Let $G$ be a countable discrete sofic group. We define a concept of uniform mixing for measure-preserving $G$-actions and show that it implies completely positive sofic entropy. When $G$ contains an element of infinite order, we use this to…

Dynamical Systems · Mathematics 2016-11-04 Tim Austin , Peter Burton

This paper is aim to extend Kenneth R. Berg's findings on the maximal entropy theorem and the ergodicity of measure convolution to the case of surjective homomorphisms. We further explores dynamical systems under surjective homomorphism in…

Dynamical Systems · Mathematics 2024-03-22 Binghui Xiao

We define a notion of entropy for an infinite family $\mathcal{C}$ of measurable sets in a probability space. We show that the mean ergodic theorem holds uniformly for $\mathcal{C}$ under every ergodic transformation if and only if…

Dynamical Systems · Mathematics 2014-03-12 Terrence M. Adams , Andrew B. Nobel

Let $G$ be a closed permutation group on a countably infinite set $\Omega$, which acts transitively but not highly transitively. If $G$ is oligomorphic, has no algebraicity and weakly eliminates imaginaries, we prove that any probability…

Dynamical Systems · Mathematics 2023-11-29 Colin Jahel , Matthieu Joseph

In this paper, we show that for several interesting systems beyond uniform hyperbolicity, any generic continuous function has a unique maximizing measure with zero entropy. In some cases, we also know that the maximizing measure has full…

Dynamical Systems · Mathematics 2020-05-25 Dawei Yang , Jinhua Zhang

Given a uniformly expanding transitive Markov interval map, we show that within the set of ergodic measures the set of nonadapted ergodic measures is residual in with respect to the topology induced by the $\overline{d}$-metric. This set of…

Dynamical Systems · Mathematics 2026-02-23 Łukasz Krzywoń

We prove a general result about the decomposition on ergodic components of group actions on boundaries of spherically homogeneous rooted trees. Namely, we identify the space of ergodic components with the boundary of the orbit tree…

Group Theory · Mathematics 2015-02-19 Rostislav Grigorchuk , Dmytro Savchuk

We investigate ergodic theory of Poisson suspensions. In the process, we establish close connections between finite and infinite measure preserving ergodic theory. Poisson suspensions thus provide a new approach to infinite measure…

Dynamical Systems · Mathematics 2008-02-26 Emmanuel Roy

We show that the endomorphisms of a compact connected group that extend to endomorphisms of every compact overgroup are precisely the trivial one and the inner automorphisms; this is an analogue, for compact connected groups, of results due…

Group Theory · Mathematics 2023-09-26 Alexandru Chirvasitu