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We prove that uniform metastability is equivalent to all closed subspaces being pseudocompact and use this to provide a topological proof of the metatheorem introduced by Caicedo, Duenez and Iovino on uniform metastability and countable…

Logic · Mathematics 2020-04-15 Clovis Hamel , Franklin D. Tall

For a measure space $(\Omega ,\Sigma ,\mu)$ and a bijective increasing function $\varphi :\left[ 0,\infty \right) \rightarrow \left[0,\infty \right)$ the $L^{p}$-like paranormed ($F$-normed) function space with the paranorm of the form…

Functional Analysis · Mathematics 2013-05-28 Justyna Jarczyk , Janusz Matkowski

We consider some natural connections which arise between right-flat (p, q) paraconformal structures and integrable systems. We find that such systems may be formulated in Lax form, with a "Lax p-tuple" of linear differential operators,…

solv-int · Physics 2007-05-23 James D. E. Grant

In this note a notion of generalized topological entropy for arbitrary subsets of the space of all sequences in a compact topological space is introduced. It is shown that for a continuous map on a compact space the generalized topological…

Dynamical Systems · Mathematics 2024-10-29 Maysam Maysami Sadr , Mina Shahrestani

The property of countable metacompactness of a topological space gets its importance from Dowker's 1951 theorem that the product of a normal space X with the unit interval is again normal iff X is countably metacompact. In a recent paper,…

Logic · Mathematics 2024-05-29 Rodrigo Carvalho , Tanmay Inamdar , Assaf Rinot

Haver's near-selection theorem deals with approximate selections of Hausdorff continuous CE-valued mappings defined on $\sigma$-compact metrizable $C$-spaces. In the present paper, we extend this theorem to all paracompact $C$-spaces. The…

General Topology · Mathematics 2019-12-10 Valentin Gutev

Characterisations of metrizable topological spaces or metrizable uniform spaces are well known. A natural counterpart to being metrizable for topological spaces can be expressed in terms of probabilistic metrizability for approach spaces.…

General Topology · Mathematics 2026-01-13 Eva Colebunders , Robert Lowen

As already mentioned by Lawvere in his 1973 paper, the characterisation of Cauchy completeness of metric spaces in terms of representability of adjoint distributors amounts to the idempotent-split property of an ordinary category when the…

Category Theory · Mathematics 2025-10-02 Dirk Hofmann , Walter Tholen

We prove existence of extension dimension for paracompact spaces. Here is the main result of the paper: \proclaim{Theorem} Suppose X is a paracompact space. There is a CW complex K such that {a.} K is an absolute extensor of X up to…

General Topology · Mathematics 2008-02-27 Jerzy Dydak

We introduce a general notion of covering property, of which many classical definitions are particular instances. Notions of closure under various sorts of convergence, or, more generally, under taking kinds of accumulation points, are…

General Topology · Mathematics 2022-06-28 Paolo Lipparini

We give a constructive proof for the following new collar theorem: every locally collared closed set that is paracompact in a Hausdorff space is collared. This includes the important special case of locally collared closed sets in…

General Topology · Mathematics 2023-08-25 Martin Werner Licht

This paper provides two characterizations of regularity for near-vector spaces: first, by expressing them as a direct sum of vector spaces over division rings formed by distributive elements; second, by expressing their dimension in term of…

Rings and Algebras · Mathematics 2024-07-25 Leandro Boonzaaier , Sophie Marques , Daniella Moore

We are mainly interested here in Kazhdan's property T for measured equivalence relations. Among our main results are characterizations of strong ergodicity and Kazhdan's property in terms of the spectra of diffusion operators, associated to…

Dynamical Systems · Mathematics 2007-05-23 Mikael Pichot

We characterize Morita equivalence of theories in the sense of Johnstone in terms of a new syntactic notion of a common definitional extension developed by Barrett and Halvorson for cartesian, regular, coherent, geometric and first-order…

Logic · Mathematics 2015-07-10 Dimitris Tsementzis

The class $\mathfrak C $ relative to countably compact topological spaces and the class $\mathfrak P$ relative to pseudocompact spaces introduced by Z. Frol\'ik are naturally generalized relative to every topological property. We provide a…

General Topology · Mathematics 2015-03-10 Paolo Lipparini

Motivated by Sarnak's conjecture on M\"obius orthogonality, we investigate the general problem of orthogonality for a bounded sequence to topological models of characteristic classes of measure-preserving automorphisms. Our main observation…

Dynamical Systems · Mathematics 2026-04-24 J. Aaronson , A. I. Danilenko , J. Kułaga-Przymus , M. Lemańczyk

The aim of this paper is to introduce a new class of softly normal called softly $\pi g\widehat{D}$ -normality by using $\pi g\widehat{D}$ -open sets and obtained several properties of such a space. We discuss many properties of this new…

General Topology · Mathematics 2025-06-12 Neeraj Kumar Tomar , Fahed Zulfeqarr , M. C. Sharma

The main results of this paper show that various coarse (`large scale') geometric properties are closely related. In particular, we show that property A implies the operator norm localisation property, and thus that norms of operators…

Metric Geometry · Mathematics 2012-03-29 Jacek Brodzki , Graham A. Niblo , Jan Spakula , Rufus Willett , Nick J. Wright

The property of a normal functor to be open-multicommutative proposed by Kozhan and Zarichnyi (2004) is investigated. A number of normal functors related to the functor of probability measures and equipped with convex structure are…

General Topology · Mathematics 2007-05-23 Roman Kozhan

We extend the hotspot lemma, or Piatetski\u{i}-Shapiro normality criterion, to dynamical systems on non-compact spaces. We build on the work of N. G. Moshchevitin and I. D. Shkredov, noting an issue in some of their proofs, and adding a…

Dynamical Systems · Mathematics 2019-12-24 Dylan Airey , Bill Mance