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Related papers: Amenability, proximality and higher order syndetic…

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We introduce inner amenability for discrete p.m.p. groupoids and investigate its basic properties, examples, and the connection with central sequences in the full group of the groupoid or central sequences in the von Neumann algebra…

Operator Algebras · Mathematics 2020-05-27 Yoshikata Kida , Robin Tucker-Drob

We consider definable topological dynamics for $NIP$ groups admitting certain decompositions in terms of specific classes of definably amenable groups. For such a group, we find a description of the Ellis group of its universal definable…

Logic · Mathematics 2019-02-20 Grzegorz Jagiella

This paper continues math.GR/0608302's study of amenability of affine algebras (based on the notion of almost-invariant finite-dimensional subspace), and applies it to graded algebras associated with finitely generated groups. Due to a…

Group Theory · Mathematics 2008-04-02 Laurent Bartholdi

M. Beiglb\"ock, V. Bergelson, and A. Fish proved that if $G$ is a countable amenable group and $A$ and $B$ are subsets of $G$ with positive Banach density, then the product set $AB$ is piecewise syndetic. This means that there is a finite…

Combinatorics · Mathematics 2015-08-10 Mauro Di Nasso , Isaac Goldbring , Renling Jin , Steven Leth , Martino Lupini , Karl Mahlburg

We study amenability of affine algebras (based on the notion of almost-invariant finite-dimensional subspace), and apply it to algebras associated with finitely generated groups. We show that a group G is amenable if and only if its group…

Group Theory · Mathematics 2009-11-27 Laurent Bartholdi

We introduce a notion of entropy for automorphisms of discrete groups which admit amenable actions on a compact space. This entropy is dual to classical topological entropy in the sense that if G is discrete and abelian then our notion of…

Operator Algebras · Mathematics 2007-05-23 N. P. Brown , E. Germain

We study amenability of definable and topological groups. Among our main technical tools is an elaboration on and strengthening of the Massicot-Wagner version of the stabilizer theorem, and some results around measures. As an application we…

Logic · Mathematics 2021-11-23 Ehud Hrushovski , Krzysztof Krupiński , Anand Pillay

We show that amenability of a group acting by homeomorphisms can be deduced from a certain local property of the action and recurrency of the orbital Schreier graphs. This covers amenability of a wide class groups, the amenability of which…

Group Theory · Mathematics 2017-10-05 Kate Juschenko , Volodymyr Nekrashevych , Mikael de la Salle

We introduce the notions of u-amenability and hyper-u-amenability for countable Borel equivalence relations, strong forms of amenability that are implied by hyperfiniteness. We show that treeable, hyper-u-amenable countable Borel…

Logic · Mathematics 2026-02-03 Petr Naryshkin , Andrea Vaccaro

Structurally stable (rough) flows on surfaces have only finitely many singularities and finitely many closed orbits, all of which are hyperbolic, and they have no trajectories joining saddle points. The violation of the last property leads…

Dynamical Systems · Mathematics 2017-06-07 Vladislav Kruglov , Dmitry Malyshev , Olga Pochinka

To any finite ordered subset and any finite partition of a group a set of tuples of positive integers, named as configurations, is associated that describes the group's behavior. The present paper provides an exposition of this notion and…

Group Theory · Mathematics 2018-04-24 Akram Yousofzadeh

To an ergodic, essentially free and measure-preserving action of a non-amenable Baumslag-Solitar group on a standard probability space, a flow is associated. The isomorphism class of the flow is shown to be an invariant of such actions of…

Group Theory · Mathematics 2015-01-05 Yoshikata Kida

The purpose of this paper is to study the notion of relative extreme amenability for pairs of topological groups. We give a characterization by a fixed point property on universal spaces. In addition we introduce the concepts of an…

Group Theory · Mathematics 2015-01-09 Yonatan Gutman , Lionel Nguyen Van Thé

Different notions of amenability on hypergroups and their relations are studied. Developing Leptin's theorem for discrete hypergroups, we characterize the existence of a bounded approximate identity for hypergroup Fourier algebras. We study…

Functional Analysis · Mathematics 2016-02-29 Mahmood Alaghmandan

The present paper develops two concepts of pointwise differentiability of higher order for arbitrary subsets of Euclidean space defined by comparing their distance functions to those of smooth submanifolds. Results include that…

Differential Geometry · Mathematics 2019-04-11 Ulrich Menne

We prove several results on the permanence of weak amenability and the Haagerup property for discrete quantum groups. In particular, we improve known facts on free products by allowing amalgamation over a finite quantum subgroup. We also…

Operator Algebras · Mathematics 2014-11-18 Amaury Freslon

In this paper it is proved that near a compact, invariant, proper subset of a continuous flow on a compact, connected metric space, at least one, out of twenty eight relevant dynamical phenomena, will necessarily occur. This result shows…

Dynamical Systems · Mathematics 2012-02-14 Pedro Teixeira

We provide a quantitative formulation of the equivalence between hyperlinearity and soficity for amenable groups, effectively showing how every hyperlinear approximation to such a group is simulated by a suitable sofic approximation. The…

Group Theory · Mathematics 2024-01-12 Peter Burton , Maksym Chaudkhari , Kate Juschenko , Kyrylo Muliarchyk

This paper demonstrates the uniformly finite homology developed by Block and Weinberger and its relationship to amenable spaces via applications to the Cayley graph of Thompson's Group F. In particular, a certain class of subgraph of F is…

Group Theory · Mathematics 2009-03-11 Dan Staley

Let K be a fine hyperbolic graph and G be a group acting on K with finite quotient. We prove that G is exact provided that all vertex stabilizers are exact. In particular, a relatively hyperbolic group is exact if all its peripheral groups…

Group Theory · Mathematics 2007-05-23 Narutaka Ozawa