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We prove that a compact space $K$ embeds into a $\sigma$-product of compact metrizable spaces ($\sigma$-product of intervals) if and only if $K$ is (strongly countable-dimensional) hereditarily metalindel\"of and every subspace of $K$ has a…

General Topology · Mathematics 2025-03-13 Antonio Avilés , Mikołaj Krupski

We show that, given a nonmetrizable compact space $K$ having $\omega$-derived set empty, there always exist nontrivial exact sequences $0\to c_0\to E\to C(K)\to 0$. This partially solves a problem posed in several papers: Is $Ext(C(K),…

Functional Analysis · Mathematics 2016-01-12 Jesús M. F. Castillo

Certain notions of convergence of sequences functions such as pointwise convergence and (uniform) convergence on compact or bounded sets come from suitable topological function spaces; see [1]. Under certain conditions these topologies…

General Mathematics · Mathematics 2025-12-22 Luis David Rivera

It is shown that the existence of a biseparating map between a large class of spaces of vector-valued continuous functions A(X,E) and A(Y,F) implies that some compactifications of X and Y are homeomorphic. In some cases, conditions are…

General Topology · Mathematics 2007-05-23 Jesus Araujo

Let $X$ be a zero-dimensional metric space and $X'$ its derived set. We prove the following assertions: (1) the space $C_k(X,2)$ is an Ascoli space iff $C_k(X,2)$ is $k_\mathbb{R}$-space iff either $X$ is locally compact or $X$ is not…

Functional Analysis · Mathematics 2015-04-22 S. Gabriyelyan

A space is called minimal if it admits a minimal continuous selfmap. We give examples of metrizable continua $X$ admitting both minimal homeomorphisms and minimal noninvertible maps, whose squares $X\times X$ are not minimal, i.e., they…

Dynamical Systems · Mathematics 2020-05-15 Matúš Dirbák , Ľubomír Snoha , Vladimír Špitalský

A compact space $X$ is said to be minimal if there exists a map $f:X\to X$ such that the forward orbit of any point is dense in $X$. We consider rigid minimal spaces, motivated by recent results of Downarowicz, Snoha, and Tywoniuk [J. Dyn.…

Dynamical Systems · Mathematics 2020-02-13 J. P. Boroński , Jernej Činč , Magdalena Foryś-Krawiec

Motivated by results of J. R. Kline and R. L. Moore (1919) that a compact subset of the plane, homeomorphic to a subset of the reals, lies on the arc, we give a purely topological characterisation of compact sets of the reals. This allows…

General Topology · Mathematics 2023-12-21 Wojciech Bielas , Mateusz Kula , Szymon Plewik

A topological space $X$ is cometrizable if it admits a weaker metrizable topology such that each point $x\in X$ has a (not necessarily open) neighborhood base consisting of metrically closed sets. We study the relation of cometrizable…

General Topology · Mathematics 2020-04-07 Taras Banakh , Yaryna Stelmakh

We say that a metrizable space $M$ is a Krasinkiewicz space if any map from a metrizable compactum $X$ into $M$ can be approximated by Krasinkiewicz maps (a map $g\colon X\to M$ is Krasinkiewicz provided every continuum in $X$ is either…

General Topology · Mathematics 2008-03-28 Eiichi Matsuhashi , Vesko Valov

A compact set has computable type if any homeomorphic copy of the set which is semicomputable is actually computable. Miller proved that finite-dimensional spheres have computable type, Iljazovi\'c and other authors established the property…

Logic · Mathematics 2023-07-10 Djamel Eddine Amir , Mathieu Hoyrup

In this note we prove that a regular continuous open image of the Sorgenfrey line with an uncountable weight has a closed subspace that is homeomorphic to the Sorgenfrey line. As a corollary we deduce the theorem in the title.

General Topology · Mathematics 2021-10-26 Vlad Smolin

A topological space ${\mathcal X}$ is reversible iff each continuous bijection (condensation) $f: {\mathcal X} \rightarrow {\mathcal X}$ is a homeomorphism; weakly reversible iff whenever ${\mathcal Y}$ is a space and there are…

General Topology · Mathematics 2024-12-11 Miloš S. Kurilić

There are two main subjects in this paper. 1) For a topological dynamical system $(X,T)$ we study the topological entropy of its "functional envelopes" (the action of $T$ by left composition on the space of all continuous self-maps or on…

Dynamical Systems · Mathematics 2015-03-12 Tomasz Downarowicz , L'ubomir Snoha , Dariusz Tywoniuk

We show that on a totally disconnected compact metric space every separating homeomorphisms is expansive except at periodic points. We conclude that minimal separating homeomorphisms are expansive and that every separating homeomorphism has…

Dynamical Systems · Mathematics 2017-07-21 Alfonso Artigue

The deck, $\mathcal{D}(X)$, of a topological space $X$ is the set $\mathcal{D}(X)=\{[X \setminus \{x\}]\colon x \in X\}$, where $[Y]$ denotes the homeomorphism class of $Y$. A space $X$ is (topologically) reconstructible if whenever…

General Topology · Mathematics 2015-10-12 Paul Gartside , Max F. Pitz , Rolf Suabedissen

It is known that the classical Banach--Stone theorem does not extend to the class of $AC(\sigma)$ spaces of absolutely continuous functions defined on compact subsets of the complex plane. On the other hand, if $\sigma$ is restricted to the…

Functional Analysis · Mathematics 2018-10-23 Ian Doust , Shaymaa Al-shakarchi

For a Tychonoff space $X$, we denote by $C_k(X)$ the space of all real-valued continuous functions on X with the compact-open topology. In this paper, we have gave characterization for $C_k(X)$ to satisfy $S_{fin}(S, S)$.

General Topology · Mathematics 2018-05-16 Alexander V. Osipov

We prove that there is a compact space $L$ and a 1-complemented subspace of the Banach space $C(L)$ which is not isomorphic to a space of continuous functions.

Functional Analysis · Mathematics 2023-05-09 Grzegorz Plebanek , Alberto Salguero Alarcón

For a Tychonoff space $X$, let $C_k(X)$ and $C_p(X)$ be the spaces of real-valued continuous functions $C(X)$ on $X$ endowed with the compact-open topology and the pointwise topology, respectively. If $X$ is compact, the classic result of…

Functional Analysis · Mathematics 2018-09-25 Saak Gabriyelyan , Jerzy Kcakol
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