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Related papers: Influence of ideals in compactifications

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We introduce the notion of compactifiable classes -- these are classes of metrizable compact spaces that can be up to homeomorphic copies ``disjointly combined'' into one metrizable compact space. This is witnessed by so-called compact…

General Topology · Mathematics 2020-02-19 A. Bartoš , J. Bobok , J. van Mill , P. Pyrih , B. Vejnar

In this paper, constructing a class of ideals of $B_1(X)$ from proper ideals of $C(X)$ a one-one correspondence between the class of real maximal ideals of $C(X)$ and those of $B_1(X)$ is established. The collection of all real maximal…

General Topology · Mathematics 2023-07-18 A. Deb Ray , Atanu Mondal

Answering questions raised in \cite{Leonetti, Uzcategui} we characterize ideals $\mathcal I\subseteq \mathcal P(\omega)$ such that $c_{0,\mathcal I}$ is complemented in $\ell_\infty$ as exactly those ideals for which the space $K_{\mathcal…

Functional Analysis · Mathematics 2025-12-02 Michael Hrušák , Luis Sáenz

If $\mathcal P$ is a family of filters over some set $I$, a topological space $X$ is \emph{sequencewise $\mathcal P$-\brfrt compact} if, for every $I$-indexed sequence of elements of $X$, there is $F \in \mathcal P$ such that the sequence…

General Topology · Mathematics 2016-08-30 Paolo Lipparini

We present a study of semigroup compactifications of a semitopological semigroup $S$ using certain filters on $S$. We characterize closed subsemigroups and closed left, right, and two-sided ideals in any semigroup compactification of any…

General Topology · Mathematics 2013-07-12 Tomi Alaste

We introduce a compactification of the space of simple positive divisors on a Riemann surface, as well as a compactification of the universal family of punctured surfaces above this space. These are real manifolds with corners. We then…

Differential Geometry · Mathematics 2020-09-02 Rafe Mazzeo , Xuwen Zhu

Every topological group $G$ has some natural compactifications which can be a useful tool of studying $G$. We discuss the following constructions: (1) the greatest ambit $S(G)$ is the compactification corresponding to the algebra of all…

General Topology · Mathematics 2007-05-23 Vladimir Uspenskij

For a domain $G$ in the one-point compactification $\overline{\mathbb{R}}^n = \mathbb{R}^n \cup \{ \infty\}$ of $\mathbb{R}^n, n \ge 2$, we characterize the completeness of the modulus metric $\mu_G$ in terms of a potential-theoretic…

Complex Variables · Mathematics 2022-06-06 Toshiyuki Sugawa , Matti Vuorinen , Tanran Zhang

Let $X$ be a (topological) space and let ${\mathscr I}$ be an ideal in $X$, that is, a collection of subsets of $X$ which contains all subsets of its elements and is closed under finite unions. The elements of ${\mathscr I}$ are called…

Functional Analysis · Mathematics 2014-01-27 M. R. Koushesh

The aim of the paper is to characterize (pre)compactness in the spaces of Lipschitz/H\"older continuous mappings acting from a compact metric space to a normed space. To this end some extensions and generalizations of already existing…

Functional Analysis · Mathematics 2023-06-21 Jacek Gulgowski , Piotr Kasprzak , Piotr Maćkowiak

This paper explores recent progress related to constraint maps. Building on the exposition in [14], our goal is to provide a clear and accessible account of some of the more intricate arguments behind the main results in this work. Along…

Analysis of PDEs · Mathematics 2025-07-01 Alessio Figalli , André Guerra , Sunghan Kim , Henrik Shahgholian

The possibility of extending operations of topological and semitopological algebras to their Stone-\v{C}ech compactification and factorization of continuous functions through homomorphisms to metrizable algebras are investigated. Most…

General Topology · Mathematics 2024-06-11 Evgenii Reznichenko

Given an ideal $\mathcal{I}$ on $\omega$, we prove that a sequence in a topological space $X$ is $\mathcal{I}$-convergent if and only if there exists a ``big'' $\mathcal{I}$-convergent subsequence. Then, we study several properties and show…

Classical Analysis and ODEs · Mathematics 2019-02-19 Paolo Leonetti , Fabio Maccheroni

A complete contraction on a C*-algebra A, which preserves all closed two sided ideals J, can be approximated pointwise by elementary complete contractions if and only if the induced map on the tensor product of B with A/J is contractive for…

Operator Algebras · Mathematics 2009-02-03 Bojan Magajna

In this paper we study the existence and uniqueness of fixed points of a class of mappings defined on complete, (sequentially compact) cone metric spaces, without continuity conditions and depending on another function.

Functional Analysis · Mathematics 2009-06-12 José R. Morales , Edixon Rojas

We introduce fibrewise compactifications in both the setting of locally compact Hausdorff spaces and continuous maps, and the parallel setting of $C^*$-algebras and nondegenerate multiplier-valued $*$-homomorphisms. In both situations, we…

Operator Algebras · Mathematics 2025-04-29 Alexander Mundey

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

Previously, the authors used the insights of Robinson's non-standard analysis as a powerful tool to extend and simplify the construction of some compactifications of regular spaces. They now show that any Hausdorff compactification is…

General Topology · Mathematics 2020-09-11 Matt Insall , Peter A. Loeb , Malgorzata Aneta Marciniak

The first author introduced a measure of compactness for families of sets, relative to a class of filters, in the context of convergence approach spaces. We characterize a variety of maps (types of quotient maps, closed maps, and variants…

General Topology · Mathematics 2015-07-28 Frédéric Mynard , William Trott

In this paper we have studied the idea of ideal completeness of function spaces Y to the power X with respect to pointwise uniformity and uniformity of uniform convergence. Further involving topological structure on X we have obtained…

General Topology · Mathematics 2017-04-19 Amar Kumar Banerjee , Apurba Banerjee