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In this paper, we study a class of Banach spaces, called \phi-spaces. In a natural way, we associate a measure of weak compactness in such spaces and prove an analogue of Sadovskii fixed point theorem for weakly sequentially continuous…

Functional Analysis · Mathematics 2007-05-23 Cleon S. Barroso , Donal O'Regan

In the paper, we recall the Wallman compactification of a Tychonoff space $T$ (denoted by $\text{Wall}(T)$) and the contribution made by Gillman and Jerison. Motivated by the Gelfand-Naimark theorem, we investigate the homeomorphism between…

General Topology · Mathematics 2016-05-10 Mateusz Krukowski

We study the closure of the convex hull of a compact set in a complete CAT(0) space. First we give characterization results in terms of compact sets and the closure of their convex hulls for locally compact CAT(0) spaces that are either…

Metric Geometry · Mathematics 2021-09-14 Arian Bërdëllima

We propose a point-free approach to MV-topological spaces in the wake of previous works on both classical and fuzzy topology. In order to do that, we introduce suitable frame-type structures and a class of fuzzy topological spaces which…

Logic · Mathematics 2026-04-02 Marby Zuley Bolaños Ortiz , Luz Victoria De La Pava , Ciro Russo

Let $X$ be a space. A space $Y$ is called an extension of $X$ if $Y$ contains $X$ as a dense subspace. For an extension $Y$ of $X$ the subspace $Y\backslash X$ of $Y$ is called the remainder of $Y$. Two extensions of $X$ are said to be…

General Topology · Mathematics 2012-07-26 M. R. Koushesh

We investigate weak and strong structures for generalized topological spaces, among others products, sums, subspaces, quotients, and the complete lattice of generalized topologies on a given set. Also we introduce $T_{3.5}$ generalized…

General Topology · Mathematics 2016-04-14 E. Makai, , E. Peyghan , B. Samadi

In the absence of the axiom of choice, the set-theoretic status of many natural statements about metrizable compact spaces is investigated. Some of the statements are provable in $\mathbf{ZF}$, some are shown to be independent of…

General Topology · Mathematics 2020-08-05 Kyriakos Keremedis , Eleftherios Tachtsis , Eliza Wajch

There are different definitions of ends in non-locally-finite graphs which are all equivalent in the locally finite case. We prove the compactness of the end-topology that is based on the principle of removing finite sets of vertices and…

Combinatorics · Mathematics 2009-10-31 B. Krön

In this paper we examine two basic topological properties of partial metric spaces, namely compactness and completeness. Our main result claims that in these spaces compactness is equivalent to sequential compactness. We also show that…

General Topology · Mathematics 2022-02-01 Dariusz Bugajewski , Piotr Maćkowiak , Ruidong Wang

The concept of convex compactness, weaker than the classical notion of compactness, is introduced and discussed. It is shown that a large class of convex subsets of topological vector spaces shares this property and that is can be used in…

Functional Analysis · Mathematics 2010-06-02 Gordan Zitkovic

The equivalence of the Choice Axiom and Tychonov compactness was proved by Kelley in 1950. Tychonov compactness is required to prove existence of the minimiser of an action functional under standard hypotheses. Solutions to the inviscid…

General Mathematics · Mathematics 2010-07-15 John M. Noble

In this note we shall prove that the Stone-\v{C}ech compactification of $\mathcal{L}^n$ is the space $\bar{\mathcal{L}}^n$ where $\bar{\mathcal{L}}$ is the extended long line, namely, $\mathcal{L}$ together with its ends $\pm \Omega$. We…

General Topology · Mathematics 2009-04-02 Veerendra Vikram Awasthi , Parameswaran Sankaran

We give a new proof of the Kat\v{e}tov-Tong theorem. Our strategy is to first prove the theorem for compact Hausdorff spaces, and then extend it to all normal spaces. The key ingredient is how the ring of bounded continuous real-valued…

General Topology · Mathematics 2020-01-27 Guram Bezhanishvili , Patrick J. Morandi , Bruce Olberding

In this paper Lowen type multi-fuzzy topological space has been introduced and characterization of topology by its nbd system is studied. Also the product multi-fuzzy topological space has been introduced and it has been investigated that…

General Mathematics · Mathematics 2018-04-17 Moumita Chiney , S. K. Samanta

For the set C(X) of real-valued continuous functions on a Tychonoff space X, the compact-open topology on C(X) is a "set-open topology". This paper studies the separation and countability properties of the space C(X) having the topology…

General Topology · Mathematics 2016-04-07 Anubha Jindal , R. A. McCoy , S. Kundu

For a $C_0(X)$-algebra $A$, we study $C(K)$-algebras $B$ that we regard as compactifications of $A$, generalising the notion of (the algebra of continuous functions on) a compactification of a completely regular space. We show that $A$…

Operator Algebras · Mathematics 2016-04-11 David McConnell

In this brief note we provide a simple approach to give a new proof of the well known fact that the Banach-Alaoglu theorem and the Tychonoff product theorem for compact Hausdorff spaces are equivalent.

General Topology · Mathematics 2009-11-25 Stefano Rossi

For a topological space $X$ a topological contraction on $X$ is a closed mapping $f:X\to X$ such that for every open cover of $X$ there is a positive integer $n$ such that the image of the space $X$ via the $n$th iteration of $f$ is a…

General Topology · Mathematics 2026-02-04 Michał Morayne , Robert Rałowski

In these expository notes, intended for students without background in point-set topology, we develop the basic theory of the Stone-Cech compactification without reference to open sets, closed sets, filters, or nets. In particular, this…

General Topology · Mathematics 2012-09-14 Michael Shulman

In this paper, we discuss a rigidity property for holomorphic disks in Teichm\"uller space. In fact, we give a refinement of Tanigawa's rigidity theorem. We will also treat the rigidity property of holomorphic disks for complex manifolds.…

Complex Variables · Mathematics 2014-02-25 Hideki Miyachi