English
Related papers

Related papers: Amenable actions, free products and a fixed point …

200 papers

In this paper we investigate the interrelation between the topological freedom of partial actions of discrete groups and faithful representations of partial crossed products.

Operator Algebras · Mathematics 2007-05-23 A. V. Lebedev

Let G be an infinite discrete countable amenable group acting continuously on a Lebesgue space X. In this article, using partition and factor-space, the conditional entropy of the action G is defined. We introduction some properties of…

Dynamical Systems · Mathematics 2025-05-06 Yuan Lian , Bin Zhu

We introduce a family of atomic measures on free groups generated by no-return random walks. These measures are shown to be very convenient for comparing "relative sizes" of subgroups, context-free and regular subsets (that, subsets…

Group Theory · Mathematics 2007-05-23 Alexandre V. Borovik , Alexei G. Myasnikov , Vladimir N. Remeslennikov

We examine the question of which finitely generated groups act properly on a finite product of simplicial trees, considering both arbitrary trees and where all trees are locally finite. In the second case we present evidence in favour of…

Group Theory · Mathematics 2019-10-11 J. Button

We study the fundamental problem of fairly allocating a multiset $\mathcal{M}$ of $t$ types of indivisible items among $d$ groups of agents, where all agents within a group have identical additive valuations. Gorantla et al. [GMV23] showed…

Computer Science and Game Theory · Computer Science 2026-03-09 Egor Gagushin , Marios Mertzanidis , Alexandros Psomas

In this paper we survey some recent results on actions of finite groups on topological manifolds. Given an action of a finite group $G$ on a manifold $X$, these results provide information on the restriction of the action to a subgroup of…

Geometric Topology · Mathematics 2023-12-19 Ignasi Mundet i Riera

We introduce the notion of Zimmer amenability for actions of discrete quantum groups on von Neumann algebras. We prove generalizations of several fundamental results of the theory in the noncommutative case. In particular, we give a…

Operator Algebras · Mathematics 2018-03-20 Mohammad S. M. Moakhar

We examine the selective screenability property in topological groups. In the metrizable case we also give characterizations in terms of the Haver property and finitary Haver property respectively relative to left-invariant metrics. We…

General Topology · Mathematics 2008-01-09 Liljana Babinkostova

It was proved that for any finite set of elements of a free product of residually finite groups such that no two of them belong to conjugate cyclic subgroups and each of them do not belong to a subgroup which is conjugate a to free factor…

Group Theory · Mathematics 2010-11-04 Vladimir V. Yedynak

We prove pointwise and maximal ergodic theorems for probability measure preserving (p.m.p.) actions of any countable group, provided it admits an essentially free, weakly mixing amenable action of stable type $III_1$. We show that this…

Dynamical Systems · Mathematics 2011-12-30 Lewis Bowen , Amos Nevo

We investigate Matui-Sato's notion of property (SI) for C*-dynamics, this time with a focus on actions of possibly non-amenable groups. The main result is a generalization of earlier work: For any countable group $\Gamma$ and any…

Operator Algebras · Mathematics 2023-10-12 Gábor Szabó

We prove that finitely generated amenable groups acting on CAT(0) spaces satisfy the following alternative: either every action on a geodesically complete CAT(0) space with bounded geometry (or finite dimension) has a global fixed point, or…

Group Theory · Mathematics 2026-03-30 Hiroyasu Izeki , Ran Ji , Anders Karlsson , Yunhui Wu

It has recently been proved that the class of unital exact C*-algebras is closed under taking reduced amalgamated free products. In particular, this implied that the class of exact discrete groups is closed under taking amalgamated free…

Operator Algebras · Mathematics 2007-05-23 Ken Dykema

We prove that a group acting geometrically on a thick affine building has property (T). A more general criterion for property (T) is given for groups acting on partite complexes.

Group Theory · Mathematics 2024-10-10 Izhar Oppenheim

We describe a flexible construction that produces triples of finitely generated, residually finite groups $M\hookrightarrow P \hookrightarrow \Gamma$, where the maps induce isomorphisms of profinite completions…

Group Theory · Mathematics 2024-12-18 Martin R. Bridson

An action of a group $G$ on a set $X$ is called ``decent'' if every subgroup of $G$ with a finite orbit in $X$ fixes a point in $X$ and every finitely generated subgroup of $G$ such that every element of the subgroup fixes a point of $X$…

Group Theory · Mathematics 2026-04-27 Chris Karpinski

We give a criterion for group elements to have fixed points with respect to a semi-simple action on a complete CAT(0) space of finite topological dimension. As an application, we show that Thompson's group T and various generalizations of…

Group Theory · Mathematics 2020-07-15 Motoko Kato

In this paper, we study discrete spectrum of invariant measures for countable discrete amenable group actions. We show that an invariant measure has discrete spectrum if and only if it has bounded measure complexity. We also prove that,…

Dynamical Systems · Mathematics 2019-08-23 Tao Yu , Guohua Zhang , Ruifeng Zhang

We characterize amenability of subspaces of $C(S)$, where $S$ is a semitopological semigroup, in terms of fixed point properties of nonexpansive actions. In particular, we give a complete characterization of a semitopological semigroup with…

Functional Analysis · Mathematics 2019-09-24 Andrzej Wiśnicki

We establish $\mathcal{Z}$-stability for crossed products of outer actions of amenable groups on $\mathcal{Z}$-stable $C^*$-algebras under a mild technical assumption which we call McDuff property with respect to invariant traces. We obtain…

Operator Algebras · Mathematics 2022-09-29 Eusebio Gardella , Shirly Geffen , Petr Naryshkin , Andrea Vaccaro