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Related papers: Scale pressure for amenable group actions

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A new flavour of amenability for discrete semigroups is proposed that generalises group amenability and follows from a \Folner-type condition. Some examples are explored, to argue that this new notion better captures some essential ideas of…

Group Theory · Mathematics 2016-04-27 Josh Deprez

An action trace is a function naturally associated to a probability measure preserving action of a group on a standard probability space. For countable amenable groups, we characterise stability in permutations using action traces. We…

Group Theory · Mathematics 2024-12-13 Goulnara Arzhantseva , Liviu Paunescu

In this paper, we introduce the notions of lowerable, D-lowerable, P-lowerable, hereditarily lowerable, and hereditarily uniformly lowerable for countably infinite amenable group actions. We show that a system with finite entropy is…

Dynamical Systems · Mathematics 2026-01-29 Xiaochen Wang

The conformal anomaly and anomaly-induced effective action represent useful and economic ways to describe semiclassical contributions to the action of gravity. We discuss the anomaly in the case when the background is formed by metric and…

High Energy Physics - Theory · Physics 2023-12-20 Manuel Asorey , Wagno Cesar e Silva , Ilya L. Shapiro , Públio R. B. do Vale

We completely characterize connected Lie groups all of whose countable subgroups are weakly amenable. We also provide a characterization of connected semisimple Lie groups that are weakly amenable. Finally, we show that a connected Lie…

Functional Analysis · Mathematics 2018-10-17 Søren Knudby

Let $\Gamma$ be a countable group acting on a countable set $X$ by permutations. We give a necessary and sufficient condition for the action to have a quasi-invariant mean with a given cocycle. This can be viewed as a combinatorial analogue…

Functional Analysis · Mathematics 2011-10-11 Gabor Elek , Adam Timar

In this note we extend the concept of topological stability from homeomorphisms to group actions on compact metric spaces, and prove that if an action of a finitely generated group is expansive and has the pseudo-orbit tracing property then…

Dynamical Systems · Mathematics 2016-11-29 Nhan-Phu Chung , Keonhee Lee

In the first part of this paper, we let $G$ be a finitely-generated amenable group such that $G/[G, G]$ is torsion-free. We suppose that $G$ acts by homeomorphisms homotopic to the identity on a manifold $M$, and give conditions on $M$…

Geometric Topology · Mathematics 2015-07-20 Kiran Parkhe

A group is said to be strongly amenable if each of its proximal topological actions has a fixed point. We show that a finitely generated group is strongly amenable if and only if it is virtually nilpotent. More generally, a countable…

Group Theory · Mathematics 2020-01-08 Joshua Frisch , Omer Tamuz , Pooya Vahidi Ferdowsi

It is shown that the restriction of the action of any group with finite orbit on the minimal sets of dendrites is equicontinuous. Consequently, we obtain that the action of any amenable group and Thompson group on dendrite restricted on…

Dynamical Systems · Mathematics 2019-04-15 el Houcein el Abdalaoui , Issam Naghmouchi

Let G be a countable group. We proof that there is a model companion for the approximate theory of a Hilbert space with a group G of automorphisms. We show that G is amenable if and only if the structure induced by countable copies of the…

Logic · Mathematics 2007-05-23 Alexander Berenstein

Generalizing Block and Weinberger's characterization of amenability we introduce the notion of uniformly finite homology for a group action on a compact space and use it to give a homological characterization of topological amenability for…

Group Theory · Mathematics 2010-12-14 Jacek Brodzki , Graham A. Niblo , Piotr Nowak , Nick J. Wright

It is well known that if $G$ is a countable amenable group and $G \curvearrowright (Y, \nu)$ factors onto $G \curvearrowright (X, \mu)$, then the entropy of the first action must be greater than or equal to the entropy of the second action.…

Dynamical Systems · Mathematics 2014-07-07 Brandon Seward

This note describes the first example of a group that is amenable, but cannot be obtained by subgroups, quotients, extensions and direct limits from the class of groups locally of subexponential growth. It has a balanced presentation…

Group Theory · Mathematics 2007-05-23 Laurent Bartholdi

We extend F{\o}lner's amenability criterion to the realm of general topological groups. Building on this, we show that a topological group $G$ is amenable if and only if its left translation action can be approximated in a uniform manner by…

Group Theory · Mathematics 2019-02-20 Friedrich Martin Schneider , Andreas Thom

We provide sufficient conditions for the multi-EGS groups to be liftable and thus produce new examples of groups acting transitively on regular trees of finite degree stabilizing one of the ends, whose closures are scale groups as defined…

Group Theory · Mathematics 2024-12-18 Arsalan Akram Malik , Dmytro Savchuk

We establish the conditions under which scalable spin squeezing can be achieved in interacting spin ensembles embedded in arbitrary, inhomogeneous graph geometries. We identify two different forms of squeezing: OAT-like scalable squeezing…

Quantum Physics · Physics 2026-05-26 Andrea Solfanelli , Augusto Smerzi , Peter Zoller , Nicolò Defenu

We investigate amenability for $W^*$-Fell bundles over a discrete group $G$, with a focus on its characterization via approximation properties and conditional expectations. Building on the notion of $W^*$-amenability, we construct an…

Operator Algebras · Mathematics 2025-12-19 Alcides Buss , Damián Ferraro

It is proved that positive entropy implies mean Li-Yorke chaos for a G-system, where G is a countable infinite discrete bi-orderable amenable group. Examples are given for the cases of integer lattice groups and groups of integer unipotent…

Dynamical Systems · Mathematics 2015-04-13 Wen Huang , Lei Jin

We introduce and study the class of spherically ordered groups. The notions of spherically ordered groups and their spectra of spherical orderability are introduced. Values of these spectra are found for a series of natural groups.

Group Theory · Mathematics 2024-07-19 Sergey V. Sudoplatov