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Related papers: Exactness of locally compact groups

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In this article it is proved, that every locally compact second countable group has a left invariant metric d, which generates the topology on G, and which is proper, ie. every closed d-bounded set in G is compact. Moreover, we obtain the…

Operator Algebras · Mathematics 2007-05-23 Uffe Haagerup , Agata Przybyszewska

A locally compact groupoid is said to be exact if its associated reduced crossed product functor is exact. In this paper, we establish some permanence properties of exactness, including generalizations of some known results for exact…

Operator Algebras · Mathematics 2018-11-07 Scott M. LaLonde

We show that in order to prove that every second countable locally compact groups with exact reduced group C*-algebra is exact in the dynamical sense (i.e. KW-exact) it suffices to show this for totally disconnected groups.

Group Theory · Mathematics 2018-03-20 Chris Cave , Joachim Zacharias

We examine sufficient conditions for the dual of a topological group to be metrizable and locally compact.

General Topology · Mathematics 2016-03-01 Frédéric Mynard , Mikhail Tkachenko

It is proved that a discrete group G is exact if and only if its left translation action on the Stone-Cech compactification is amenable. Combining this with an unpublished result of Gromov, we have the existence of non exact discrete…

Operator Algebras · Mathematics 2009-10-31 Narutaka Ozawa

We demonstrate that And\'ujar Guerrero, Thomas and Walsberg's results on definable compactness in o-minimal structures still hold true in definably complete locally o-minimal structures. As an application, we show that a definably simple…

Logic · Mathematics 2024-11-22 Masato Fujita

We investigate what it means for a (Hausdorff, second-countable) topological group to be computable. We compare several potential definitions in the literature. We relate these notions with the well-established definitions of effective…

Logic · Mathematics 2025-04-16 Heer Tern Koh , Alexander Melnikov , Keng Meng Ng

It is known that exactness for a discrete group is equivalent to C*-exactness, i.e., the exactness of its reduced C*-algebra. The problem of whether this equivalence holds for general locally compact groups has recently been reduced by Cave…

Operator Algebras · Mathematics 2021-03-29 Nicholas Manor

We prove that a closed subgroup $H$ of a second countable locally compact group $G$ is amenable if and only if its left regular representation on an Orlicz space $L^\Phi(G)$ for some $\Delta_2$-regular $N$-function $\Phi$ almost has…

Representation Theory · Mathematics 2013-10-01 Yaroslav Kopylov

We prove that every topological action of a countable group on a metrizable space can be realized as a bi-Lipschitz action with respect to some compatible metric. This extends a result due to U. Hamenst\"{a}dt regarding finitely generated…

Group Theory · Mathematics 2024-10-11 Inhyeok Choi , Sang-hyun Kim

A result due to M. Gromov states that any two finitely generated groups {\Gamma} and {\Lambda} are quasi-isometric if and only if they admit a topological coupling, i.e., a commuting pair of proper continuous cocompact actions…

Group Theory · Mathematics 2016-10-11 Uri Bader , Christian Rosendal

we prove that if $X$ is a locally compact $\sigma$-compact space then on its quotient, $\gamma(X)$ say, determined by the algebra of all real valued bounded continuous functions on $X$, the quotient topology and the completely regular…

General Topology · Mathematics 2008-11-21 Aldo J. Lazar

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

This article is concerned with measure equivalence and uniform measure equivalence of locally compact, second countable groups. We show that two unimodular, locally compact, second countable groups are measure equivalent if and only if they…

Group Theory · Mathematics 2019-11-19 Juhani Koivisto , David Kyed , Sven Raum

We show that if a (locally compact) group $G$ acts properly on a locally compact $\sigma$-compact space $X$ then there is a family of $G$-invariant proper continuous finite-valued pseudometrics which induces the topology of $X$. If $X$ is…

Metric Geometry · Mathematics 2014-02-26 Herbert Abels , Antonios Manoussos , Gennady Noskov

We say that an action of a countable discrete inverse semigroup on a locally compact Hausdorff space is amenable if its groupoid of germs is amenable in the sense of Anantharaman-Delaroche and Renault. We then show that for a given inverse…

Operator Algebras · Mathematics 2015-10-14 Ruy Exel , Charles Starling

In this paper, we firstly discuss the question: Is $l_{2}^{\infty}$ homeomorphic to a rectifiable space or a paratopological group? And then, we mainly discuss locally compact rectifiable spaces, and show that a locally compact and…

General Topology · Mathematics 2011-10-10 Fucai Lin , Chuan Liu , Shou Lin

We revisit the definition of effective local compactness, and propose an approach that works for arbitrary countably-based spaces extending the previous work on computable metric spaces. We use this to show that effective local compactness…

Logic in Computer Science · Computer Science 2019-03-14 Arno Pauly

Hrushovski proved the Lie model theorem in full generality with model theoretic methods. The theorem states that for every approximate group there exists a generalized definable locally compact model, which, simplifying, is a…

Logic · Mathematics 2025-12-17 Beatrice Degasperi

We study locally compact contractive local groups, that is, locally compact local groups with a contractive pseudo-automorphism. We prove that if such an object is locally connected, then it is locally isomorphic to a Lie group. We also…

Differential Geometry · Mathematics 2009-10-08 Lou van den Dries , Isaac Goldbring
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