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In this paper we introduce and study so-called $k^*$-metrizable spaces forming a new class of generalized metric spaces, and display various applications of such spaces in topological algebra, functional analysis, and measure theory. By…

General Topology · Mathematics 2011-10-11 T. O. Banakh , V. I. Bogachev , A. V. Kolesnikov

Given a metric space $\langle X,\rho \rangle$, consider its hyperspace of closed sets $CL(X)$ with the Wijsman topology $\tau_{W(\rho)}$. It is known that $\langle{CL(X),\tau_{W(\rho)}}\rangle$ is metrizable if and only if $X$ is separable…

General Topology · Mathematics 2015-03-27 Rodrigo Hernández-Gutiérrez , Paul Szeptycki

This article concerns a class of metric spaces, which we call multigeodesic spaces, where between any two distinct points there exist multiple distinct minimising geodesics. We provide a simple characterisation of multigeodesic normed…

Metric Geometry · Mathematics 2025-05-07 Amlan Banaji

If $X$ is a (topological) space, the $n$th finite subset space of $X$, denoted by $X(n)$, consists of $n$-point subsets of $X$ (i.e., nonempty subsets of cardinality at most $n$) with the quotient topology induced by the unordering map…

General Topology · Mathematics 2024-08-20 Earnest Akofor

A metric space $\mathbf{X}$ is called densely complete if there exists a dense set $D$ in $\mathbf{X}$ such that every Cauchy sequence of points of $D $ converges in $\mathbf{X}$. One of the main aims of this work is to prove that the…

General Topology · Mathematics 2019-01-28 Kyriakos Keremedis , Eliza Wajch

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

A metric space $X$ is {\em injective} if every non-expanding map $f:B\to X$ defined on a subspace $B$ of a metric space $A$ can be extended to a non-expanding map $\bar f:A\to X$. We prove that a metric space $X$ is a Lipschitz image of an…

General Topology · Mathematics 2024-05-28 Judyta Bąk , Taras Banakh , Joanna Garbulińska-Węgrzyn , Magdalena Nowak , Michał Popławski

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

In this manuscript, we claim that the newly introduced $\mathcal{F}$-metric space \cite[\, M.~Jleli and B.~Samet, On a new generalization of metric spaces, J. Fixed Point Theory Appl, 20(3) 2018]{JS1} is metrizable. Also, we deduce that the…

Functional Analysis · Mathematics 2018-08-09 Sumit Som , Ashis Bera , Lakshmi Kanta Dey

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

The main purpose of this paper is to find the fixed point in such cases where existing literature remain silent. In this paper we introduce partial completeness, a new type of contraction and many other definitions. Using this approach the…

Functional Analysis · Mathematics 2018-03-23 Tawseef Rashid , Qamrul Haque Khan

Let $\mathcal{I}$ be an analytic P-ideal [respectively, a summable ideal] on the positive integers and let $(x_n)$ be a sequence taking values in a metric space $X$. First, it is shown that the set of ideal limit points of $(x_n)$ is an…

Classical Analysis and ODEs · Mathematics 2018-11-27 Paolo Leonetti

It is shown that there exists a normal uniform algebra, on a compact metrizable space, that fails to be strongly regular at some peak point. This answers a 31-year-old question of Joel Feinstein. Our example is R(K) for a certain compact…

Complex Variables · Mathematics 2024-10-09 Alexander J. Izzo

This is a report of a joint work with E. J\"arvenp\"a\"a, M. J\"arvenp\"a\"a, T. Rajala, S. Rogovin, and V. Suomala. In [3], we characterized uniformly porous sets in $s$-regular metric spaces in terms of regular sets by verifying that a…

Classical Analysis and ODEs · Mathematics 2017-01-31 Antti Käenmäki

We show that any metacompact Moore space is monotonically metacompact and use that result to characterize monotone metacompactness in certain generalized ordered (GO)spaces. We show, for example, that a generalized ordered space with a…

General Topology · Mathematics 2011-08-29 Harold R. Bennett , Klaas Pieter Hart , David J. Lutzer

For a metrizable space $X$ of density $\kappa$, let $PM(X)$ be the space of continuous bounded pseudometrics on $X$ endowed with the uniform convergence topology. In this paper, its topology shall be classified as follows: (i) If $X$ is…

General Topology · Mathematics 2022-05-25 Katsuhisa Koshino

A metric space is indivisible if for any partition of it into finitely many pieces one piece contains an isometric copy of the whole space. Continuing our investigation of indivisible metric spaces, we show that a countable ultrametric…

Metric Geometry · Mathematics 2007-05-23 Christian Delhommé , Claude Laflamme , Maurice Pouzet , Norbert Sauer

In this paper, we prove that the topology induced by algebraic cone metric coincides with the topology induced by the metric obtained via a nonlinear scalarization function, i.e. any algebraic cone metric space is metrizable. Furthermore,…

Functional Analysis · Mathematics 2014-02-04 Saeedeh Shamsi Gamchi , Mohammad Janfada , Assadollah Niknam

We show that if there exists a topologically expansive homeomorphism on a uniform space, then the space is always a regular space. Through examples we show that in general composition of topologically expansive homeomorphisms need not be…

Dynamical Systems · Mathematics 2019-03-26 Ali Barzanouni , Ekta Shah

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