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Related papers: Nice enumerations and extreme amenability

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We introduce a topology on the space of all isomorphism types represented in a given class of countable models, and use this topology as an aid in classifying the isomorphism types. This mixes ideas from effective descriptive set theory and…

Logic · Mathematics 2019-08-20 Russell Miller

We introduce and study several amenability properties for unitary corepresentations and *-representations of algebraic quantum groups, which may be used to characterize amenability or co-amenability of such groups. As a background for this…

Operator Algebras · Mathematics 2007-05-23 E. Bedos , R. Conti , L. Tuset

We provide a new characterization of amenability for countable groups, based on frame representations admitting almost invariant vectors. By relaxing the frame inequalities, thereby weakening amenability, we obtain a large class of…

Group Theory · Mathematics 2025-12-03 Dorin Ervin Dutkay , Catalin Georgescu , Gabriel Picioroaga

We study hereditary properties of the class of countable groups admitting an amenable, transitive and faithful action on a countable set. We consider mainly the case of amalgamated free products, and we show in particular that the double of…

Group Theory · Mathematics 2010-04-29 Soyoung Moon

Amenability is a geometric property of convex cones that is stronger than facial exposedness and assists in the study of error bounds for conic feasibility problems. In this paper we establish numerous properties of amenable cones, and…

Optimization and Control · Mathematics 2022-10-17 Bruno F. Lourenço , Vera Roshchina , James Saunderson

Given a polynomial endomorphism F of the n-dimensional affine space over a field K, we define a sequence of polynomial endomorphisms of the affine space associated to F. We call F nice if there exists an integer m such that the m-th term of…

Algebraic Geometry · Mathematics 2016-01-07 Elzbieta Adamus , Pawel Bogdan , Teresa Crespo , Zbigniew Hajto

Erling Folner proved that the amenability or nonamenability of a countable group depends on the complexity of its finite subsets. Complexity has three measures: maximum Folner ratio, optimal cooling function, and minimum cooling norm. Our…

Group Theory · Mathematics 2012-01-04 J. W. Cannon , W. J. Floyd , W. R. Parry

In this paper we classify countable locally finite-by-abelian groups up to coarse isomorphism. This classification is derived from a coarse classification of amenable shift-homogeneous metric spaces.

Metric Geometry · Mathematics 2014-12-16 Taras Banakh , Matija Cencelj , Dušan Repovš , Ihor Zarichnyi

We will review the main results concerning the automorphism groups of saturated structures which were obtained during the two last decades. The main themes are: the small index property in the countable and uncountable cases; the…

Logic · Mathematics 2007-05-23 Daniel Lascar

Recent research in coarse geometry revealed similarities between certain concepts of analysis, large scale geometry, and topology. Property A of G.Yu is the coarse analog of amenability for groups and its generalization (exact spaces) was…

Metric Geometry · Mathematics 2014-01-07 M. Cencelj , J. Dydak , A. Vavpetič

The interrelations between various classes of convergence spaces defined by countability conditions are studied. Remarkably, they all find characterizations in the usual space of ultrafilters in terms of classical topological properties.…

General Topology · Mathematics 2021-01-13 Frédéric Mynard

The objective of this series is to study metric geometric properties of (coarse) disjoint unions of amenable Cayley graphs. We employ the Cayley topology and observe connections between large scale structure of metric spaces and group…

Group Theory · Mathematics 2019-03-13 Masato Mimura , Hiroki Sako

The first part of this article deals with theorems on uniqueness in law for \sigma-finite and constructive countable random sets, which in contrast to the usual assumptions may have points of accumulation. We discuss and compare two…

Probability · Mathematics 2012-07-24 Philip Herriger

We give the first examples of (non-amenable group) amenable actions on stably finite simple C*-algebras. More precisely, we give such actions for any countable group in an explicit way. The main ingredients of our construction are the full…

Operator Algebras · Mathematics 2026-02-09 Yuhei Suzuki

We extend the Kechris--Pestov--Todor\v{c}evi\'c correspondence to weak Fra\"{\i}ss\'{e} categories and automorphism groups of generic objects. The new ingredient is the weak Ramsey property. We demonstrate the theory on several examples…

Logic · Mathematics 2024-11-20 Adam Bartoš , Tristan Bice , Keegan Dasilva Barbosa , Wiesław Kubiś

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

We extend the classical Baire category approach, used in proving the finite generator theorem of Krieger, the homomorphism theorem of Sinai and the isomorphism theorem of Ornstein, applying a similar reasoning to the case of actions of…

Dynamical Systems · Mathematics 2024-06-21 Dawid Huczek , Sebastian Kopacz , Jacek Serafin

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

In this paper, we show that there is a net for amenable transformation groups like F{\o}lner net for amenable groups and investigate amenability of a transformation group constructed by semidirect product of groups. We introduce inner…

Functional Analysis · Mathematics 2026-04-10 Ali Ebadian , Ali Jabbari

We answer an open question of Grigorchuk and Zuk about amenability using random walks. Our results separate the class of amenable groups from the closure of subexponentially growing groups under the operations of group extension and direct…

Group Theory · Mathematics 2011-11-10 Laurent Bartholdi , Balint Virag