English
Related papers

Related papers: Coarse medians and Property A

200 papers

The objective of this series is to study metric geometric properties of disjoint unions of amenable Cayley graphs by group properties of the Cayley accumulation points in the space of marked groups. In this Part II, we prove that a disjoint…

Group Theory · Mathematics 2019-03-15 Masato Mimura , Hiroki Sako

We study product set growth in groups with acylindrical actions on quasi-trees and, more generally, hyperbolic spaces. As a consequence, we show that for every surface $S$ of finite type, there exist $\alpha,\beta>0$ such that for any…

Group Theory · Mathematics 2025-09-24 Alice Kerr

In this paper, we study the relation between the uniform Roe algebra and the uniform quasi-local algebra associated to a metric space of bounded geometry. In the process, we introduce a weakening of the notion of expanders, called…

Operator Algebras · Mathematics 2020-04-02 Kang Li , Piotr Nowak , Ján Špakula , Jiawen Zhang

A new class of groups, the locally finitely determined groups of local similarities on compact ultrametric spaces, is introduced and it is proved that groups in this class have the Haagerup property (that is, they are a-T-menable in the…

Group Theory · Mathematics 2012-06-12 Bruce Hughes

We introduce a geometric property complementary-finite asymptotic dimension (coas- dim). Similar with asymptotic dimension, we prove the corresponding coarse invariant theorem, union theorem and Hurewicz-type theorem.

Metric Geometry · Mathematics 2017-10-23 Yan Wu , Jingming Zhu

We prove the congruence subgroup property for the centralizer of a finite subgroup $G$ in the mapping class group of a hyperbolic oriented and connected surface of finite topological type $S$ such that the genus of the quotient surface…

Geometric Topology · Mathematics 2026-01-15 Marco Boggi

We construct finitely generated groups with strong fixed point properties. Let $\mathcal{X}_{ac}$ be the class of Hausdorff spaces of finite covering dimension which are mod-$p$ acyclic for at least one prime $p$. We produce the first…

Group Theory · Mathematics 2014-11-11 G. Arzhantseva , M. R. Bridson , T. Januszkiewicz , I. J. Leary , A. Minasyan , J. Swiatkowski

Property FW is a natural combinatorial weakening of Kazhdan's Property T. We prove that the group of piecewise homographic self-transformations of the real projective line, has "few" infinite subgroups with Property FW. In particular, no…

Dynamical Systems · Mathematics 2021-05-11 Yves Cornulier

We say that a finitely generated group $G$ has property (QT) if it acts isometrically on a finite product of quasi-trees so that orbit maps are quasi-isometric embeddings. A quasi-tree is a connected graph with path metric quasi-isometric…

Group Theory · Mathematics 2020-10-15 Mladen Bestvina , Kenneth Bromberg , Koji Fujiwara

We study countable embedding-universal and homomorphism-universal structures and unify results related to both of these notions. We show that many universal and ultrahomogeneous structures allow a concise description (called here a finite…

Combinatorics · Mathematics 2010-09-06 Jan Hubicka

The large-scale geometry of hyperbolic metric spaces exhibits many distinctive features, such as the stability of quasi-geodesics (the Morse Lemma), the visibility property, and the homeomorphism between visual boundaries induced by a…

Metric Geometry · Mathematics 2019-01-29 Bruce Kleiner , Urs Lang

We prove that the category of quasi-pseudometric modular spaces whose morphisms are the nonexpansive mappings is isomorphic to a quantale enriched category. To achieve this, we construct an appropriate quantale of isotone functions. We also…

Category Theory · Mathematics 2026-05-01 César López-Pastor , Tatiana Pedraza , Jesús Rodríguez-López

We prove that a minimal second countable ample groupoid has dynamical comparison if and only if its type semigroup is almost unperforated. Moreover, we investigate to what extent a not necessarily minimal almost finite groupoid has an…

Dynamical Systems · Mathematics 2021-09-14 Pere Ara , Christian Bönicke , Joan Bosa , Kang Li

A coarse group is a group endowed with a coarse structure so that the group multiplication and inversion are coarse mappings. Let $(X, \mathcal{E})$ be a coarse space and let $\mathfrak{M}$ be a variety of groups different from the variety…

General Topology · Mathematics 2018-03-29 Igor Protasov , Ksenia Protasova

We study the large-scale geometry of mapping class groups of surfaces of infinite type, using the framework of Rosendal for coarse geometry of non locally compact groups. We give a complete classification of those surfaces whose mapping…

Geometric Topology · Mathematics 2023-09-06 Kathryn Mann , Kasra Rafi

Hierarchically hyperbolic spaces (HHSs) are a large class of spaces that provide a unified framework for studying the mapping class group, right-angled Artin and Coxeter groups, and many 3--manifold groups. We investigate strongly…

Group Theory · Mathematics 2021-06-18 Jacob Russell , Davide Spriano , Hung Cong Tran

Coarse geometry, and in particular coarse homotopy theory, has proven to be a powerful tool for approaching problems in geometric group theory and higher index theory. In this paper, we continue to develop theory in this area by proving a…

Geometric Topology · Mathematics 2025-03-03 Thomas Weighill

For a discrete metric space (or more generally a large scale space) $X$ and an action of a group $G$ on $X$ by coarse equivalences, we define a type of coarse quotient space $X_G$, which agrees up to coarse equivalence with the orbit space…

Geometric Topology · Mathematics 2017-10-05 Logan Higginbotham , Thomas Weighill

Let A be a finite dimensional algebra over a field of characteristic zero graded by a finite abelian group G. Here we study a growth function related to the graded polynomial identities satisfied by A by computing the exponential rate of…

Rings and Algebras · Mathematics 2009-03-12 Eli Aljadeff , Antonio Giambruno , Daniela La Mattina

We prove that the full automorphism group and the outer automorphism group of the free group of countably infinite rank are coarsely bounded. That is, these groups admit no continuous actions on a metric space with unbounded orbits, and…

Group Theory · Mathematics 2023-04-11 George Domat , Hannah Hoganson , Sanghoon Kwak