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We define a local analogue to Gromov's loop division property which is use to give a sufficient condition for an asymptotic cone of a complete geodesic metric space to have uncountable fundamental group. As well, this property is used to…

Group Theory · Mathematics 2014-10-01 Greg Conner , Curt Kent

Sofic groups generalise both residually finite and amenable groups, and the concept is central to many important results and conjectures in measured group theory. We introduce a topological notion of a sofic boundary attached to a given…

Group Theory · Mathematics 2026-04-28 Vadim Alekseev , Martin Finn-Sell

We show that the asymptotic dimension of box spaces behaves (sub)additively with respect to extensions of groups. As a result, we obtain that for an elementary amenable group, the asymptotic dimension of any of its box spaces is bounded…

Metric Geometry · Mathematics 2015-08-21 Martin Finn-Sell , Jianchao Wu

We find an upper bound for the asymptotic dimension of a hyperbolic metric space with a set of geodesics satisfying a certain boundedness condition studied by Bowditch. The primary example is a collection of tight geodesics on the curve…

Geometric Topology · Mathematics 2014-02-26 Gregory Bell , Koji Fujiwara

In this note we give a simple argument for the fact that the coarse assembly map for a strong coarse homology theory with weak transfers and a bornological coarse space of weakly finite homotopical asymptotic dimension is a phantom…

Algebraic Topology · Mathematics 2024-12-17 Ulrich Bunke

We introduce the notion of dynamic asymptotic dimension growth for actions of discrete groups on compact spaces, and more generally for locally compact \'etale groupoids. Using the work of Bartels, L\"uck, and Reich, we bridge asymptotic…

Dynamical Systems · Mathematics 2025-02-04 Hang Wang , Yanru Wang , Jianguo Zhang , Dapeng Zhou

We characterise when there exists a quasiisometric embedding between two solvable Baumslag-Solitar groups. This extends the work of Farb and Mosher on quasiisometries between the same groups. More generally, we characterise when there can…

Group Theory · Mathematics 2022-04-11 Patrick S. Nairne

We show that for a countable discrete group which is locally of finite asymptotic dimension, the generic continuous action on Cantor space has hyperfinite orbit equivalence relation. In particular, this holds for free groups, answering a…

Logic · Mathematics 2024-09-06 Sumun Iyer , Forte Shinko

We introduce dynamic asymptotic dimension, a notion of dimension for actions of discrete groups on locally compact spaces, and more generally for locally compact \'etale groupoids. We study our notion for minimal actions of the integer…

Dynamical Systems · Mathematics 2015-10-28 Erik Guentner , Rufus Willett , Guoliang Yu

Given a bi-invariant metric on a group, we construct a version of an asymptotic cone without using ultrafilters. The new construction, called the directional asymptotic cone, is a contractible topological group equipped with a complete…

Group Theory · Mathematics 2023-08-07 Jarek Kędra , Assaf Libman

In this paper, we develop a coarse analogue of treewidth. We prove that a graph $G$ admits a tree-decomposition in which each bag is contained in the union of a bounded number of balls of bounded radius, if and only if $G$ admits a…

Combinatorics · Mathematics 2025-09-08 Tung Nguyen , Alex Scott , Paul Seymour

Using uniformization, Cantor type sets can be regarded as boundaries of rooted trees. In this setting, we show that the trace of a first-order Sobolev space on the boundary of a regular rooted tree is exactly a Besov space with an explicit…

Functional Analysis · Mathematics 2017-05-08 Anders Björn , Jana Björn , James T. Gill , Nageswari Shanmugalingam

We use geometric measure theory to introduce the notion of asymptotic cones associated with a singular subspace of a Riemannian manifold. This extends the classical notion of asymptotic directions usually defined on smooth submanifolds. We…

Differential Geometry · Mathematics 2015-01-13 Xiang Sun , Jean-Marie Morvan

It is well-known that a paracompact space X is of covering dimension n if and only if any map f from X to a simplicial complex K can be pushed into its n-skeleton. We use the same idea to define dimension in the coarse category. It turns…

Metric Geometry · Mathematics 2019-11-18 M. Cencelj , J. Dydak , A. Vavpetic

A topological space is nonseparably connected if it is connected but all of its connected separable subspaces are singletons. We show that each connected first countable space is the image of a nonseparably connected complete metric space…

Metric Geometry · Mathematics 2009-11-05 T. Banakh , M. Vovk , M. R. Wójcik

We extend Gromov's notion of asymptotic dimension of finitely generated groups to all discrete groups. In particular, we extend the Hurewicz type theorem proven in [B-D2] to general groups. Then we use this extension to prove a formula for…

Geometric Topology · Mathematics 2007-05-23 A. Dranishnikov , J. Smith

A topological space is called {\it dense-separable} if each dense subset of its is separable. Therefore, each dense-separable space is separable. We establish some basic properties of dense-separable topological groups. We prove that each…

General Topology · Mathematics 2022-12-27 Fucai Lin , Qiyun Wu , Chuan Liu

Uniformity and proximity are two different ways for defining small scale structures on a set. Coarse structures are large scale counterparts of uniform structures. In this paper, motivated by the definition of proximity, we develop the…

Geometric Topology · Mathematics 2021-11-12 Sh. Kalantari , B. Honari

We prove that a set of finite perimeter is indecomposable if and only if it is, up to a choice of suitable representative, connected in the 1-fine topology. This gives a topological characterization of indecomposability which is new even in…

Metric Geometry · Mathematics 2025-12-23 Paolo Bonicatto , Panu Lahti , Enrico Pasqualetto

In this paper, we study properties of asymptotic resemblance relations induced by compatible coarse structures on groups. We generalize the notion of asymptotic dimensiongrad for groups with compatible coarse structures and show this notion…

Geometric Topology · Mathematics 2021-11-12 Sh. Kalantari