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For a compactification $\alpha X$ of a Tychonoff space $X$, the algebra of all functions $f\in C(X)$ that are continuously extendable over $% \alpha X$ is denoted by $C_{\alpha}(X)$. It is shown that, in a model of $\textbf{ZF}$, it may…

General Topology · Mathematics 2018-05-25 Kyriakos Keremedis , Eliza Wajch

A topological space $X$ is Baire if the Baire Category Theorem holds for $X$, i.e., the intersection of any sequence of open dense subsets of $X$ is dense in $X$. In this paper, we have obtained that the space $B^{st}_1(X)$ of pointwise…

General Topology · Mathematics 2022-06-06 Alexander V. Osipov

It is solved the problem on construction of separately continuous functions on product of $n$ topological spaces with given restriction. In particular, it is shown that for every topological space $X$ and $n-1$ Baire class function $g:X\to…

General Topology · Mathematics 2016-02-02 V. V. Mykhaylyuk

A topological space $X$ is called $\Cal A$-real compact, if every algebra homomorphism from $\Cal A$ to the reals is an evaluation at some point of $X$, where $\Cal A$ is an algebra of continuous functions. Our main interest lies on…

Functional Analysis · Mathematics 2016-09-06 Andreas Kriegl , Peter W. Michor

We construct a separately continuous function $e:E\times K\to\{0,1\}$ on the product of a Baire space $E$ and a zero-dimensional compact space $K$ such that no restriction of $e$ to any non-meager Borel set in $E\times K$ is continuous. The…

General Topology · Mathematics 2023-06-22 Volodymyr Mykhaylyuk , Roman Pol

In the present paper we establish that the space $\exp_\beta X$ of compact subsets of a Tychonoff space $X$ is superparacompact iff $X$ is so. Further, we prove the Tychonoff map $\exp_{\beta} f:\ \exp_{\beta} X\rightarrow \exp_{\beta} Y$…

General Topology · Mathematics 2018-11-14 Adilbek Zaitov , Davron Jumaev

A topological space $Y$ has the property (B) of Banakh if there is a countable family $\{A_n:n\in \mathbb{N}\}$ of closed nowhere dense subsets of $Y$ absorbing all compact subsets of $Y$. In this note we show that the space $C_p(X)$ of…

General Topology · Mathematics 2024-07-29 Mikołaj Krupski , Kacper Kucharski , Witold Marciszewski

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

We prove a commutative Gelfand--Naimark type theorem, by showing that the set $C_s(X)$ of continuous bounded (real or complex valued) functions with separable support on a locally separable metrizable space $X$ (provided with the supremum…

Functional Analysis · Mathematics 2015-06-26 M. R. Koushesh

For a Tychonoff space $X$ and a subspace $Y\subset\mathbb R$, we study Baire category properties of the space $C_{\downarrow F}(X,Y)$ of continuous functions from $X$ to $Y$, endowed with the Fell hypograph topology. We characterize pairs…

General Topology · Mathematics 2021-11-02 Leijie Wang , Taras Banakh

In this paper, some features of countably $\alpha$-compact topological spaces are presented and proven. The connection between countably $\alpha$% -compact, Tychonoff, and $\alpha$-Hausdorff spaces is explained. The space is countably…

General Topology · Mathematics 2022-05-25 Eman Almuhur , Muhammad Ahsan Khan

A Tychonoff space $X$ is called $\kappa$-pseudocompact if for every continuous mapping $f$ of $X$ into $\mathbb{R}^\kappa$ the image $f(X)$ is compact. This notion generalizes pseudocompactness and gives a stratification of spaces lying…

General Topology · Mathematics 2023-06-01 Mikołaj Krupski

We show that if $X$ is a separable locally compact Hausdorff connected space with fewer than $\mathfrak c$ non-cut points, then $X$ embeds into a dendrite $D\subseteq \mathbb R ^2$, and the set of non-cut points of $X$ is a nowhere dense…

General Topology · Mathematics 2019-09-25 David S. Lipham

A space $X$ is called a generalized Namioka space (g$\mathcal{N}$-space), if for every compact space $Y$ and every separately continuous function $f\colon X\times Y\rightarrow\mathbb{R}$, there exists at least one point $x\in X$ such that…

General Topology · Mathematics 2026-05-21 Xiongping Dai , Congying Lv , Yuxuan Xie

Under $\text{CH}$ we construct a partition of Baire space into compact sets, which is indestructible by countably supported iteration and product of Sacks forcing of any length, answering a question of Newelski. Further, we present an…

Logic · Mathematics 2025-05-08 Vera Fischer , Lukas Schembecker

Let $\varphi\colon X\to Y$ be an affine continuous surjection between compact convex sets. Suppose that the canonical copy of the space of real-valued affine continuous functions on $Y$ in the space of real-valued affine continuous…

Functional Analysis · Mathematics 2016-09-05 Ondřej F. K. Kalenda , Jiří Spurný

We prove some consistency results concerning the Moving Off Property for locally compact spaces and thus the question of whether their function spaces are Baire.

General Topology · Mathematics 2015-07-27 Franklin D. Tall

A space X is finite dimensional, locally compact and separable metrizable if and only if X has a finite basic family: continuous functions Phi_1,...,Phi_n of X to the reals, R, such that for all continuous f from X to R there are g_1,...,…

Functional Analysis · Mathematics 2014-02-26 Paul Gartside , Feng Ziqin

We prove that each coarsely homogenous separable metric space $X$ is coarsely equivalent to one of the spaces: the sigleton, the Cantor macro-cube or the Baire macro-space. This classification is derived from coarse characterizations of the…

Metric Geometry · Mathematics 2011-10-11 Taras Banakh , Ihor Zarichnyi

For separable metrizable spaces $X,Y$ and a metrizable topological group $Z$ by $S(X\times Y,Z)$ we denote the space of all separately continuous functions $f:X\times Y\to Z$ endowed with the topology of layer-wise uniform convergence,…

General Topology · Mathematics 2016-02-23 Taras Banakh