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We introduce a new covering property, defined in terms of order types of sequences of open sets, rather than in terms of cardinalities of families. The most general form of this compactness notion depends on two ordinal parameters. In the…

General Topology · Mathematics 2021-02-09 Paolo Lipparini

We study lattices in non-positively curved metric spaces. Borel density is established in that setting as well as a form of Mostow rigidity. A converse to the flat torus theorem is provided. Geometric arithmeticity results are obtained…

Group Theory · Mathematics 2010-01-18 P. -E. Caprace , N. Monod

In Koeller \cite{koerprops} the twelve variants of the Reifenberg properties known to be instrumental in the theory of minimal surfaces were classified with respect to various Hausdorff measure based measure theoretic properties. The…

Metric Geometry · Mathematics 2011-01-20 Amos N. Koeller

This note identifies compact and {\sigma}-compact subsets of probability measures on a class of metric spaces with respect to the weak convergence topology. Moreover, it is shown by an example, that the space of probability measures on a…

Optimization and Control · Mathematics 2023-07-17 Óscar Vega-Amaya , Fernando Luque-Vásquez

We prove that compact Hausdorff spaces with a $\mathbb{P}$-diagonal are metrizable.

General Topology · Mathematics 2016-09-02 Alan Dow , Klaas Pieter Hart

Let $G$ be a non-compact group, $K$ the compact subgroup fixed by a Cartan involution and assume $G/K$ is an exceptional, symmetric space, one of Cartan type $E,F $ or $G$. We find the minimal integer, $L(G),$ such that any convolution…

Representation Theory · Mathematics 2015-11-19 Kathryn Hare , Jimmy He

For a topological space $X$, let $X_\delta$ be the space $X$ with $G_\delta$-topology of $X$. For an uncountable cardinal $\kappa$, we prove that the following are equivalent: (1) $\kappa$ is $\omega_1$-strongly compact. (2) For every…

Logic · Mathematics 2018-07-23 Toshimichi Usuba

We call a space $X$ {\it weakly linearly Lindel\"of} if for any family $\mathcal{U}$ of non-empty open subsets of $X$ of regular uncountable cardinality $\kappa$, there exists a point $x\in X$ such that every neighborhood of $x$ meets…

General Topology · Mathematics 2016-10-17 I. Juhász , V. V. Tkachuk , R. G. Wilson

The main results of this note are: It is consistent that every subparacompact space $X$ of size $\omega_1$ is a $D$-space; If there exists a Michael space, then all productively Lindel\"of spaces have the Menger property, and, therefore,…

General Topology · Mathematics 2011-12-06 Dušan Repovš , Lyubomyr Zdomskyy

To appear in J. Funct. Spaces and Appl.

Functional Analysis · Mathematics 2008-06-27 Pascal Lefevre , Daniel Li , Herve Queffelec , Luis Rodriguez-Piazzaa

Let $(B,\|\cdot\|)$ be a Banach space, $(\Omega,\mathcal{F},P)$ a probability space and $L^0(\mathcal{F},B)$ the set of equivalence classes of strong random elements (or strongly measurable functions) from $(\Omega,\mathcal{F},P)$ to…

Functional Analysis · Mathematics 2019-04-09 Tiexin Guo , Erxin Zhang , Yachao Wang , George Yuan

Regularity properties of the pressure are related to phase transitions. In this article we study thermodynamic formalism for systems defined in non-compact phase spaces, our main focus being countable Markov shifts. We produce metric…

Dynamical Systems · Mathematics 2023-03-28 Godofredo Iommi , Mike Todd

We study the matrix range of a tuple of compact operators on a Hilbert space and examine the notions of minimal, nonsingular, and fully compressed tuples. In this pursuit, we refine previous results by characterizing nonsingular compact…

Operator Algebras · Mathematics 2019-06-21 Benjamin Passer , Orr Moshe Shalit

The aim of this paper is to introduce the concepts of homotopical smallness and closeness. These are the properties of homotopical classes of maps that are related to recent developments in homotopy theory and to the construction of…

Geometric Topology · Mathematics 2011-01-05 Ziga Virk

We say that $E$ is a microset of the compact set $K\subset \mathbb{R}^d$ if there exist sequences $\lambda_n\geq 1$ and $u_n\in \mathbb{R}^d$ such that $(\lambda_n K + u_n ) \cap [0,1]^d$ converges to $E$ in the Hausdorff metric, and…

Classical Analysis and ODEs · Mathematics 2021-04-21 Richárd Balka , Márton Elekes , Viktor Kiss

We study locally compact metric spaces that enjoy various forms of homogeneity with respect to M\"obius self-homeomorphisms. We investigate connections between such homogeneity and the combination of isometric homogeneity with…

Metric Geometry · Mathematics 2018-12-11 David Freeman , Enrico Le Donne

The density topology $\cal T$ is a topology on the real line, finer than the usual topology, having as its open sets the measurable subsets of ${\mathbb R}$, which are of density 1 at each of their points. The aim of this paper is to…

General Topology · Mathematics 2007-05-23 Julian Dontchev

We study paracontact metric $(\kappa,\mu)$-spaces with $\kappa=-1$, equivalent to $h^2=0$ but not $h=0$. In particular, we will give an alternative proof of Theorem 3.2 of [11] and present examples of paracontact metric $(-1,2)$-spaces and…

Differential Geometry · Mathematics 2015-07-28 Verónica Martín-Molina

In these notes, uniform convergence on compacta is studied on the space of functions taking values in the set of finite Borel measures. Related limit theorems, including L\'evy's continuity theorem and functional limit theorems for…

Probability · Mathematics 2026-01-13 Takahiro Hasebe , Ikkei Hotta , Takuya Murayama

It is common that a Sobolev space defined on $\mathbb{R}^m$ has a non-compact embedding into an $L^p$-space, but it has subspaces for which this embedding becomes compact. There are three well known cases of such subspaces, the Rellich…

Functional Analysis · Mathematics 2020-03-17 Leszek Skrzypczak , Cyril Tintarev