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We introduce multi-split continuous functions between topological spaces, a weaker form of continuity that generalizes split continuity while being stable under compositions. We will define the associated star multifunction and…

General Topology · Mathematics 2024-12-02 Finn Michler , Argha Ghosh

We first show that the projection image of a discrete definable set is again discrete for an arbitrary definably complete locally o-minimal structure. This fact together with the results in a previous paper implies tame dimension theory and…

Logic · Mathematics 2022-10-07 Masato Fujita , Tomohiro Kawakami , Wataru Komine

A separable space is strongly sequentially separable if, for each countable dense set, every point in the space is a limit of a sequence from the dense set. We consider this and related properties, for the spaces of continous and Borel…

General Topology · Mathematics 2019-11-11 Alexander V. Osipov , Piotr Szewczak , Boaz Tsaban

This paper presents a constructive proof of the existence of a regular non-atomic strictly-positive measure on any second-countable non-atomic locally compact Hausdorff space. This construction involves a sequence of finitely-additive set…

Functional Analysis · Mathematics 2020-02-21 Jason Bentley

This work establishes a structure theorem for compact K\"ahler manifolds with semipositive anticanonical bundle. Up to finite \'etale cover, it is proved that such manifolds split holomorphically and isometrically as a product of Ricci flat…

Algebraic Geometry · Mathematics 2018-02-06 Frédéric Campana , Jean-Pierre Demailly , Thomas Peternell

We show a number of undecidable assertions concerning countably compact spaces hold under PFA(S)[S]. We also show the consistency without large cardinals of "every locally compact, perfectly normal space is paracompact".

Logic · Mathematics 2016-07-18 Alan Dow , Franklin D. Tall

We prove that: 1. If a Hausdorff M-space is a continuous closed image of a submetrizable space, then it is metrizable. 2. A dense-in-itself open-closed image of a submetrizable space is submetrizable if and only if it is functionally…

General Topology · Mathematics 2023-12-07 Vlad Smolin

Hurewicz' characterized the dimension of separable metrizable spaces by means of finite-to-one maps. We investigate whether this characterization also holds in the class of compact F-spaces of weight c. Our main result is that, assuming the…

General Topology · Mathematics 2014-01-15 Klaas Pieter Hart , Jan van Mill

In a previous paper the second author introduced a compact topology on the space of closed ideals of a unital Banach algebra A. If A is separable then this topology is either metrizable or else neither Hausdorff nor first countable. Here it…

Functional Analysis · Mathematics 2007-05-23 J. F. Feinstein , D. W. B. Somerset

We examine properties of equidistant sets determined by nonempty disjoint compact subsets of a compact 2-dimensional Alexandrov space (of curvature bounded below). The work here generalizes many of the known results for equidistant sets…

Metric Geometry · Mathematics 2022-05-20 Logan S. Fox , J. J. P. Veerman

We prove that any compact Berkovich space over the field of Laurent series over an arbitrary field is angelic. In particular, is it sequentially compact.

Algebraic Geometry · Mathematics 2011-04-01 C. Favre

We prove a new version of isoperimetric inequality: Given a positive real $m$, a Banach space $B$, a closed subset $Y$ of metric space $X$ and a continuous map $f:Y \rightarrow B$ with $f(Y)$ compact $$\inf_FHC_{m+1}(F(X))\leq…

Differential Geometry · Mathematics 2021-02-26 Yevgeny Liokumovich , Boris Lishak , Alexander Nabutovsky , Regina Rotman

The Kantorovich-Rubinshtein metric is an $L^1$-like metric on spaces of probability distributions that enjoys several serendipitous properties. It is complete separable if the underlying metric space of points is complete separable, and in…

General Topology · Mathematics 2022-12-23 Jean Goubault-Larrecq

We prove that under certain set-theoretic assumptions every productively Lindel\"of space has the Hurewicz covering property, thus improving upon some earlier results of Aurichi and Tall.

General Topology · Mathematics 2014-06-04 Dušan Repovš , Lyubomyr Zdomskyy

We introduce the open degree of a compact space, and we show that for every natural number n, the separable Rosenthal compact spaces of degree n have a finite basis.

General Topology · Mathematics 2015-12-29 Antonio Avilés , Stevo Todorcevic

In \cite{Chaber}, Chaber has proved that countably compact spaces with a quasi $G_{\delta }$-diagonal are compact. We prove that initially $\kappa $% -compact spaces with a quasi $G_{\kappa }$-diagonal are compact, for any infinite cardinal…

General Topology · Mathematics 2017-05-02 Çetin Vural

Let $f\colon X\rightarrow Y$ be a continuous surjection of compact Hausdorff spaces. By $$f_*\colon\mathfrak{M}(X)\rightarrow\mathfrak{M}(Y),\ \mu\mapsto \mu\circ f^{-1} \quad{\rm and}\quad 2^f\colon2^X\rightarrow2^Y,\ A\mapsto f[A]$$ we…

Dynamical Systems · Mathematics 2024-04-30 Xiongping Dai , Yuxun Xie

An argument of A.Borel shows that every compact connected Lie group is homeomorphic to the Cartesian product of its derived subgroup and a torus. We prove a parallel result for definably compact definably connected groups definable in an…

Logic · Mathematics 2011-10-25 Marcello Mamino

In this manuscript, we claim that the newly introduced $\mathcal{F}$-metric spaces are Hausdorff and also first countable. Moreover, we assert that every separable $\mathcal{F}$-metric space is second countable. Additionally, we acquire…

Functional Analysis · Mathematics 2018-06-18 Ashis Bera , Lakshmi Kanta Dey , Hiranmoy Garai , Ankush Chanda

We study a measure-theoretic notion of connectedness for sets of finite perimeter in the setting of doubling metric measure spaces supporting a weak $(1,1)$-Poincar\'{e} inequality. The two main results we obtain are a decomposition theorem…

Metric Geometry · Mathematics 2019-07-26 Paolo Bonicatto , Enrico Pasqualetto , Tapio Rajala