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We construct a compact Hausdorff space $K$ such that the space $P(K)$ of Radon probabiblity measures on $K$ considered with the weak$^*$ topology (induced from the space of continuous functions $C(K)$) is countably tight which is a…

Functional Analysis · Mathematics 2023-12-06 Piotr Koszmider , Zdeněk Silber

We prove that the free locally convex space $L(X)$ over a metrizable space $X$ has countable tightness if and only if $X$ is separable.

General Topology · Mathematics 2014-07-08 S. S. Gabriyelyan

We study the existence of non-separable compact spaces that support a measure and are small from the topological point of view. In particular, we show that under Martin's axiom there is a non-separable compact space supporting a measure…

Logic · Mathematics 2015-11-17 Piotr Borodulin-Nadzieja , Grzegorz Plebanek

Given a compact space $K$, we denote by $P(K)$ the space of all Radon probability measures on $K$, equipped with the $weak^\ast$ topology inherited from $C(K)^\ast$. For nonmetrizable compacta $K$ even basic properties of $P(K)$ spaces…

General Topology · Mathematics 2024-07-09 Grzegorz Plebanek

Given a property $P$ of subspaces of a $T_1$ space $X$, we say that $X$ is {\em $P$-bounded} iff every subspace of $X$ with property $P$ has compact closure in $X$. Here we study $P$-bounded spaces for the properties $P \in \{\omega D,…

General Topology · Mathematics 2014-07-01 István Juhász , Lajos Soukup , Zoltán Szentmiklóssy

We show that if K is Rosenthal compact which can be represented by functions with countably many discontinuities then every Radon measure on K is countably determined. We also present an alternative proof of the result stating that every…

Functional Analysis · Mathematics 2011-04-15 Witold Marciszewski , Grzegorz Plebanek

We conjecture that the set of homogeneous probability measures on the maximal Satake compactification of an arithmetic locally symmetric space $S=\Gamma\backslash G/K$ is compact. More precisely, given a sequence of homogeneous probability…

Number Theory · Mathematics 2022-06-14 Christopher Daw , Alexander Gorodnik , Emmanuel Ullmo

A space has $\sigma$-compact tightness if the closures of $\sigma$-compact subsets determines the topology. We consider a dense set variant that we call densely k-separable. We consider the question of whether every densely k-separable…

General Topology · Mathematics 2018-10-12 Alan Dow , Istvan Juhasz

A uniformly continuously integrable sequence of real-valued measurable functions, defined on some probability space, is relatively compact in the $\sigma(L^1,L^\infty)$ topology. In this paper, we link such a result to weak convergence…

Functional Analysis · Mathematics 2021-08-10 Gane Samb Lo , Aladji Babacar Niang

Let (\Omega,\mu) be a finite measure space, X a Banach space, and let 1\le p<\infty. The aim of this paper is to give an elementary proof of the Diaz--Mayoral theorem that a subset V of L^p(\mu;X) is relatively compact if and only if it is…

Functional Analysis · Mathematics 2013-05-27 Jan van Neerven

In the work it is shown that the space of idempotent probability measures with compact supports is kappa-metrizable if the given Tychonoff space is kappa-metrizable. It is constructed a series of max-plus-convex subfunctors of the functor…

General Topology · Mathematics 2019-05-23 Azad Yangibayevich Ishmetov

We construct a normal countably tight $T_1$ space $X$ with $t(X_\delta) >2^\omega$. This is an answer to the question posed by Dow-Juh\'asz-Soukup-Szentmikl\'ossy-Weiss. We also show that if the continuum is not so large, then the tightness…

Logic · Mathematics 2019-07-16 Toshimichi Usuba

A topological space $X$ is said to be {\em $Y$-rigid} if any continuous map $f:X\rightarrow Y$ is constant. In this paper we construct a number of examples of regular countably compact $\mathbb R$-rigid spaces with additional properties…

General Topology · Mathematics 2021-10-11 Serhii Bardyla , Lyubomyr Zdomskyy

An $\omega_1$-compact space is a space in which every closed discrete subspace is countable. We give various general conditions under which a locally compact, $\omega_1$-compact space is $\sigma$-countably compact, i.e., the union of…

General Topology · Mathematics 2022-06-07 Peter Nyikos , Lyubomyr Zdomskyy

We investigate connections between resolvability and different forms of tightness. This study is adjacent to [1,2]. We construct a non-regular refinement $\tau^*$ of the natural topology of the real line $\mathbb{R}$ with properties such…

General Topology · Mathematics 2025-07-29 Anton Lipin

Countable tightness may be destroyed by countably closed forcing. We characterize the indestructibility of countable tightness under countably closed forcing by combinatorial statements similar to the ones Tall used to characterize…

General Topology · Mathematics 2013-10-22 Marion Scheepers

We show that there is a compact topological space carrying a measure which is not a weak* limit of finitely supported measures but is in the sequential closure of the set of such measures. We construct compact spaces with measures of…

General Topology · Mathematics 2012-09-21 Piotr Borodulin-Nadzieja , Omar Selim

A dual pair formulation for asymmetric locally convex spaces is developed that strictly generalises the ordinary vector space setting. The concept of a polar topology carries over to the asymmetric case and some familiar results are…

General Topology · Mathematics 2026-02-24 Jobst Ziebell

Michael asked whether every productively Lindel\"of space is powerfully Lindel\"of. Building of work of Alster and De la Vega, assuming the Continuum Hypothesis, we show that every productively Lindel\"of space of countable tightness is…

General Topology · Mathematics 2017-11-22 Andrea Medini , Lyubomyr Zdomskyy

Using elementary probabilistic methods, in particular a variant of the Weak Law of Large Numbers related to the Bernoulli distribution, we prove that for every infinite compact spaces $K$ and $L$ the product $K\times L$ admits a sequence…

Functional Analysis · Mathematics 2022-07-27 Jerzy Kąkol , Damian Sobota , Lyubomyr Zdomskyy
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