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Related papers: Relatively amenable actions of Thompson's groups

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We generalize Renault's notion of measurewise amenability to actions of second countable, Hausdorff, \'etale groupoids on separable $C^*$-algebras and show that measurewise amenability characterizes nuclearity of the crossed product…

Operator Algebras · Mathematics 2023-01-31 Julian Kranz

In this short note, for countably infinite amenable group actions, we provide topological proofs for the following results: Bowen topological entropy (dimensional entropy) of the whole space equals the usual topological entropy along…

Dynamical Systems · Mathematics 2017-12-19 Dou Dou , Ruifeng Zhang

Let G be a locally compact topological group and X a compact space with continuous G-action. The main result of this essay states that the following statements are equivalent : 1) The action of G on X is topologically amenable ; 2) Every…

Group Theory · Mathematics 2011-03-15 Terra Antonio

In this paper we prove that the Thompson groups $T$ and $V$ are not inner amenable. In particular, their group von Neumann algebras do not have property $\Gamma$. Moreover, we prove that if the reduced group $C^\ast$-algebra of $T$ is…

Operator Algebras · Mathematics 2016-09-19 Uffe Haagerup , Kristian Knudsen Olesen

Given a locally compact quantum group $\mathbb{G}$ and a closed quantum subgroup $\mathbb{H}$, we show that $\mathbb{G}$ is amenable if and only if $\mathbb{H}$ is amenable and $\mathbb{G}$ acts amenably on the quantum homogenous space…

Operator Algebras · Mathematics 2018-05-24 Jason Crann

We show that every non-amenable free product of groups admits free ergodic probability measure preserving actions which have relative property (T) in the sense of S.-Popa \cite[Def. 4.1]{Pop06}. There are uncountably many such actions up to…

Operator Algebras · Mathematics 2010-09-24 Damien Gaboriau

We construct an action of the Thompson group F on a compact space built from pairs of infinite, binary rooted trees. The action arises as an F-equivariant compactification of the action of F by translations on one of its homogeneous spaces,…

Operator Algebras · Mathematics 2023-03-21 Jeong Hee Hong , Wojciech Szymanski

In this work we introduce and study a new notion of amenability for actions of locally compact groups on $C^*$-algebras. Our definition extends the definition of amenability for actions of discrete groups due to Claire…

Operator Algebras · Mathematics 2022-05-04 Alcides Buss , Siegfried Echterhoff , Rufus Willett

Let $G$ be a countable discrete amenable group which acts continuously on a compact metric space $X$ and let $\mu$ be an ergodic $G-$invariant Borel probability measure on $X$. For a fixed tempered F{\o}lner sequence $\{F_n\}$ in $G$ with…

Dynamical Systems · Mathematics 2017-08-08 Dongmei Zheng , Ercai Chen

We characterize left and right amenable semigroups of polynomials of one complex variable with respect to the composition operation. We also prove a number of results about amenable semigroups of arbitrary rational functions. In particular,…

Dynamical Systems · Mathematics 2021-08-25 Fedor Pakovich

In his study of amenable unitary representations, M. E. B. Bekka asked if there is an analogue for such representations of the remarkable fixed-point property for amenable groups. In this paper, we prove such a fixed-point theorem in the…

Operator Algebras · Mathematics 2007-05-23 Anthony T. Lau , Alan L. T. Paterson

Building on previous papers by Anantharaman-Delaroche (AD) we introduce and study the notion of AD-amenability for partial actions and Fell bundles over discrete groups. We prove that the cross-sectional C*-algebra of a Fell bundle is…

Operator Algebras · Mathematics 2021-08-12 Fernando Abadie , Alcides Buss , Damián Ferraro

Let A be a Banach algebra and I be a closed ideal of A. We say that A is amenable relative to I, if A/I is an amenable Banach algebra. We study the relative amenability of Banach algebras and investigate the relative amenability of…

Functional Analysis · Mathematics 2019-12-02 Hoger Ghahramani , Wania Khodakarami , Esmaeil Feizi

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 show that group actions on many treelike compact spaces are not too complicated dynamically. We first observe that an old argument of Seidler implies that every action of a topological group $G$ on a regular continuum is null and…

Dynamical Systems · Mathematics 2019-06-05 Eli Glasner , Michael Megrelishvili

We consider the Fourier-Stietljes algebra B(G) of a locally compact group G. We show that operator amenablility of B(G) implies that a certain semitolpological compactification of G admits only finitely many idempotents. In the case that G…

Operator Algebras · Mathematics 2018-06-25 Nico Spronk

A result by Ornstein and Weiss states that a free and measure-preserving action of an amenable group on a probability space yields a decomposition of the space in disjoint images, up to a small error, analogous to the one given by the…

Dynamical Systems · Mathematics 2024-02-16 Antonio M. Scielzo

We consider endomorphism actions of arbitrary discrete semigroups on a connected metrizable topological group G. We give necessary and sufficient conditions for expansiveness of such actions when G is a Lie group or a compact…

Dynamical Systems · Mathematics 2007-05-23 Siddhartha Bhattacharya

We prove that amenability of a discrete group is equivalent to dimension flatness of certain ring inclusions naturally associated with measure preserving actions of the group. This provides a group-measure space theoretic solution to a…

Group Theory · Mathematics 2013-05-16 David Kyed , Henrik Densing Petersen

We introduce the notion of first order amenability, as a property of a first order theory $T$: every complete type over $\emptyset$, in possibly infinitely many variables, extends to an automorphism-invariant global Keisler measure in the…

Logic · Mathematics 2025-11-18 Ehud Hrushovski , Krzysztof Krupiński , Anand Pillay