English
Related papers

Related papers: On $\kappa$-pseudocompactess and uniform homeomorp…

200 papers

We show in ZF that: (i) Every subcompact metrizable space is completely metrizable, and every completely metrizable space is countably subcompact. (ii) A metrizable space X=(X,T) is countably compact iff it is countably subcompact relative…

General Topology · Mathematics 2021-02-23 Kyriakos Keremedis

The notion of $p$-compact sets arises naturally from Grothendieck's characterization of compact sets as those contained in the convex hull of a norm null sequence. The definition, due to Sinha and Karn (2002), leads to the concepts of…

Functional Analysis · Mathematics 2012-08-31 Silvia Lassalle , Pablo Turco

For a compact space $K$ we denote by $C_w(K)$ ($C_p(K)$) the space of continuous real-valued functions on $K$ endowed with the weak (pointwise) topology. In this paper we discuss the following basic question which seems to be open: Let $K$…

General Topology · Mathematics 2018-12-12 Mikołaj Krupski , Witold Marciszewski

A topological space $X$ has the strong Pytkeev property at a point $x\in X$ if there exists a countable family $\mathcal N$ of subsets of $X$ such that for each neighborhood $O_x\subset X$ and subset $A\subset X$ accumulating at $x$, there…

General Topology · Mathematics 2021-11-01 Taras Banakh , Arkady Leiderman

We prove that on the Baire space $(D^{\kappa},\pi)$, $\kappa \geq \omega_0$ where $D$ is a uniformly discrete space having $\omega _1$-strongly compact cardinal and $\pi$ denotes the product uniformity on $D^\kappa$, there exists a…

General Topology · Mathematics 2019-12-04 Ana S. Meroño

A map $f:X\to Y$ between topological spaces is defined to be {\em scatteredly continuous} if for each subspace $A\subset X$ the restriction $f|A$ has a point of continuity. We show that for a function $f:X\to Y$ from a perfectly paracompact…

Geometric Topology · Mathematics 2011-10-11 T. Banakh , B. Bokalo

We show that there are locally compact spaces that can be condensed onto separable spaces but not onto compact separable spaces. We also show that for every cardinal $\kappa$ there is a locally compact topological group of cardinality…

General Topology · Mathematics 2025-11-19 István Juhász , Jan van Mill , Lajos Soukup

We show that a linearly ordered topological space is initially \lambda-compact if and only if it is \lambda-bounded, that is, every set of cardinality $\leq \lambda$ has compact closure. As a consequence, every product of initially…

General Topology · Mathematics 2013-07-05 Paolo Lipparini

We show that the definition of caliber given by Engelking in R. Engelking, "General topology", Sigma series in pure mathematics, Heldermann, vol. 6, 1989, which we will call caliber*, differs from the traditional notion of this concept in…

General Topology · Mathematics 2023-12-29 Alejandro Ríos-Herrejón , Ángel Tamariz-Mascarúa

For a uniform space (X, $\mu$), we introduce a realcompactification of X by means of the family $U_{\mu}(X)$ of all the real-valued uniformly continuous functions, in the same way that the known Samuel compactification is given by…

General Topology · Mathematics 2017-06-02 M. Isabel Garrido , Ana S. Meroño

A result of G. Godefroy asserts that a Banach space $X$ contains an isomorphic copy of $\ell_1$ if and only if there is an equivalent norm $|||\cdot|||$ such that, for every finite-dimensional subspace $Y$ of $X$ and every $\varepsilon>0$,…

Functional Analysis · Mathematics 2021-04-29 Antonio Avilés , Gonzalo Martínez-Cervantes , Abraham Rueda Zoca

We construct a category that classifies compact Hausdorff spaces by their shape and finite topological spaces by their weak homotopy type.

Category Theory · Mathematics 2021-10-07 Pedro J. Chocano , Manuel A. Morón , Francisco R. Ruiz del Portal

Let $X$ be metrizable, $Y$ be perfectly normal and suppose that there exists a uniformly continuous surjection $T: C_{p}(X) \to C_{p}(Y)$ (resp., $T: C_{p}^*(X) \to C_{p}^*(Y)$), where $C_{p}(X)$ (resp., $C_{p}^*(X)$) denotes the space of…

General Topology · Mathematics 2025-05-06 A. Eysen , A. Leiderman , V. Valov

Let $Y$ be a metrizable space containing at least two points, and let $X$ be a $Y_{\mathcal{I}}$-Tychonoff space for some ideal $\mathcal{I}$ of compact sets of $X$. Denote by $C_{\mathcal{I}}(X,Y)$ the space of continuous functions from…

General Topology · Mathematics 2020-04-14 Saak Gabriyelyan , Alexander V. Osipov

In this paper, we have proved results similar to Tychonoff's Theorem on embedding a space of functions with the topology of pointwise convergence into the Tychonoff product of topological spaces, but applied to the function space $C(X,Y)$…

General Topology · Mathematics 2023-04-05 Mikhail Al'perin , Sergei Nokhrin , Alexander V. Osipov

In a paper by Bella, Tokg\"os and Zdomskyy it is asked whether there exists a Tychonoff space $X$ such that the remainder of $C_p(X)$ in some compactification is Menger but not $\sigma$-compact. In this paper we prove that it is consistent…

General Topology · Mathematics 2020-01-20 Angelo Bella , Rodrigo Hernández-Gutiérrez

Given a Tychonoff space $X$, let $\varrho(X)$ be the set of remote points of $X$. We view $\varrho(X)$ as a topological space. In this paper we assume that $X$ is metrizable and ask for conditions on $Y$ so that $\varrho(X)$ is homeomorphic…

General Topology · Mathematics 2018-09-19 Rodrigo Hernández-Gutiérrez , Michael Hrušák , Angel Tamariz-Mascarúa

Modifying a construction of W. Marciszewski we prove (in ZFC) that there exists a subspace of the real line $\mathbb{R}$, such that the realcompact space $C_p(X)$ of continuous real-valued functions on $X$ with the pointwise convergence…

General Topology · Mathematics 2013-12-23 Mikołaj Krupski

The Kantorovich-Rubinshtein metric is an $L^1$-like metric on spaces of probability distributions that enjoys several serendipitous properties. It is complete separable if the underlying metric space of points is complete separable, and in…

General Topology · Mathematics 2022-12-23 Jean Goubault-Larrecq

We prove that the inclusion of map(X,Y) into map(K(X),K(Y)) is continuous, where K(X) is the space of non-empty compact subsets of X (also known as the hyperspace of compact subsets of X), and both spaces of maps are endowed with the…

General Topology · Mathematics 2014-12-16 Federico Cantero