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Related papers: A weight-free characterisation of Yu's Property A

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In this note we study the natural question of when the generalised F{\o}lner sets exhibiting property A can be chosen to be subsets of the space itself. We show that for many property A spaces $X$, this is indeed possible. Specifically this…

Metric Geometry · Mathematics 2025-09-24 Graham Niblo , Nick Wright , Jiawen Zhang

Property A is a geometric property originally introduced for discrete metric spaces to provide a sufficient condition for coarse embeddability into Hilbert space, and it is defined via a F\o{}lner condition similar in spirit to the…

General Topology · Mathematics 2021-12-15 Yeong Chyuan Chung

Property A introduced by Guoliang Yu is an amenability-type property for metric spaces. In this article, we study property A for uniformly locally finite coarse spaces. Main examples of coarse spaces are a metric space, a set equipped with…

Metric Geometry · Mathematics 2013-03-29 Hiroki Sako

For uniformly dicrete metric spaces without bounded geometry we suggest a modified version of property A based on metrics of bounded geometry greater than the given metric. We show that this version still implies coarse embeddability in…

Metric Geometry · Mathematics 2025-07-15 V. Manuilov

A metric space is said to be all-set-homogeneous if any of its partial isometries can be extended to a genuine isometry. We give a classification of a certain subclass of all-set-homogeneous length spaces.

Metric Geometry · Mathematics 2025-06-10 Nina Lebedeva , Anton Petrunin

Geometric property (T) was defined by Willett and Yu, first for sequences of graphs and later for more general discrete spaces. Increasing sequences of graphs with geometric property (T) are expanders, and they are examples of coarse spaces…

Functional Analysis · Mathematics 2021-05-27 Jeroen Winkel

We first prove that for every metrizable space $X$, for every closed subset $F$ whose complement is zero-dimensional, the space $X$ can be embedded into a product space of the closed subset $F$ and a metrizable zero-dimensional space as a…

General Topology · Mathematics 2026-01-13 Yoshito Ishiki

We introduce a generalization for bounded geometry that we call bounded scale measure. We show that bounded scale measure is a coarse invariant unlike bounded geometry. We then show equivalent definitions for spaces with bounded scale…

Geometric Topology · Mathematics 2021-08-11 Kevin Sinclair , Logan Higginbotham

Property A was introduced by Yu as a non-equivariant analogue of amenability. Nigel Higson posed the question of whether there is a homological characterisation of property A. In this paper we answer Higson's question affirmatively by…

Geometric Topology · Mathematics 2014-11-11 J. Brodzki , G. A. Niblo , N. J. Wright

We characterize the uniform convergence points set of a pointwisely convergent sequence of real-valued functions defined on a perfectly normal space. We prove that if $X$ is a perfectly normal space which can be covered by a disjoint…

General Topology · Mathematics 2020-08-12 Olena Karlova

We expose a class of discrete metric spaces, for which bounded geometry is equivalent to the property A of G. Yu. This class includes the coarse disjoint union of $(\mathbb Z/2\mathbb Z)^n$, $n\in\mathbb N$, and consists of spaces of simple…

Metric Geometry · Mathematics 2025-11-21 V. Manuilov

We show that the Freiman--Ruzsa theorem, characterising finite sets with bounded doubling, leads to an alternative proof of a characterisation of Meyer sets, that is, relatively dense subsets of Euclidean spaces whose difference sets are…

Number Theory · Mathematics 2023-12-20 Jakub Konieczny

In this paper we characterize [strict] o-boundedness of the free (abelian) topological group F(X) (A(X)) as well as the free locally-convex linear topological space L(X) in terms of properties of a Tychonoff space X. These properties appear…

General Topology · Mathematics 2007-05-23 Lyubomyr Zdomskyy

Recently, a notion of the free product $X \ast Y$ of two metric spaces $X$ and $Y$ has been introduced by T. Fukaya and T. Matsuka. In this paper, we study coarse geometric permanence properties of the free product $X \ast Y$. We show that…

Functional Analysis · Mathematics 2025-05-20 Qin Wang , Jvbin Yao

We provide an expository account of Guoliang Yu's property A. The piece starts from the basic definitions, and goes on to discuss closure properties of the class of property A spaces (and groups) and the relationship of property A to coarse…

Operator Algebras · Mathematics 2008-05-09 Rufus Willett

A theorem by Wolff states that weights defined on a measurable subset of $\mathbb{R}^n$ and satisfying a Muckenhoupt-type condition can be extended into the whole space as Muckenhoupt weights of the same class. We give a complete and…

Classical Analysis and ODEs · Mathematics 2021-10-26 Emma-Karoliina Kurki , Carlos Mudarra

All spaces are assumed to be separable and metrizable. Our main result is that the statement "For every space $X$, every closed subset of $X$ has the perfect set property if and only if every analytic subset of $X$ has the perfect set…

Logic · Mathematics 2014-08-25 Andrea Medini

We prove that: 1. If a Hausdorff M-space is a continuous closed image of a submetrizable space, then it is metrizable. 2. A dense-in-itself open-closed image of a submetrizable space is submetrizable if and only if it is functionally…

General Topology · Mathematics 2023-12-07 Vlad Smolin

The Urysohn universal metric space U is characterized up to isometry by the following properties: (1) U is complete and separable; (2) U contains an isometric copy of every separable metric space; (3) every isometry between two finite…

General Topology · Mathematics 2021-08-27 Vladimir Uspenskij

We study embeddings of uniform Roe algebras which have "large range" in their codomain and the relation of those with coarse quotients between metric spaces. Among other results, we show that if $Y$ has property A and there is an embedding…

Operator Algebras · Mathematics 2021-08-27 Bruno de Mendonça Braga
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