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We prove that every complete non-compact manifold of finite volume contains a (possibly non-compact) minimal hypersurface of finite volume. The main tool is the following result of independent interest: if a region $U$ can be swept out by a…

Differential Geometry · Mathematics 2019-08-27 Gregory R. Chambers , Yevgeny Liokumovich

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

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

Let M be the countably infinite metric fan. We show that C_k(M,2) is sequential and contains a closed copy of Arens space S_2. It follows that if X is metrizable but not locally compact, then C_k(X) contains a closed copy of S_2, and hence…

General Topology · Mathematics 2010-06-01 Gary Gruenhage , Boaz Tsaban , Lyubomyr Zdomskyy

In this paper we introduce a family of examples that can be regarded as spaces of nonpositive curvature, but with the distinct quality that they are not complete as metric spaces. This amounts to the fact that they are modelled on a finite…

Metric Geometry · Mathematics 2009-08-27 Cristian Conde , Gabriel Larotonda

We describe the order type of range sets of compact ultrametrics and show that an ultrametrizable infinite topological space $(X, \tau)$ is compact iff the range sets are order isomorphic for any two ultrametrics compatible with the…

General Topology · Mathematics 2021-03-01 Oleksiy Dovgoshey , Volodymir Shcherbak

We prove that for any measurable mapping $T$ into the space of matrices with positive determinant, there is a diffeomorphism whose derivative equals $T$ outside a set of measure less than $\varepsilon$. We use this fact to prove that for…

Classical Analysis and ODEs · Mathematics 2023-12-21 Paweł Goldstein , Zofia Grochulska , Piotr Hajłasz

We introduce and study the operation, called dense amalgam, which to any tuple X_1,...,X_k of non-empty compact metric spaces associates some disconnected perfect compact metric space, denoted $\widetilde\sqcup(X_1,...,X_k)$, in which there…

Geometric Topology · Mathematics 2014-10-21 Jacek Swiatkowski

Characterizations of paracompact finite $C$-spaces via continuous selections are given. We apply these results to obtain some properties of finite $C$-spaces. Factorization theorems and a completion theorem for finite $C$- spaces are also…

General Topology · Mathematics 2016-09-07 Vesko Valov

In this note, we consider the space $H(\Omega)^{\mathbb N}$ of sequences of holomorphic functions on an open set $\Omega\subset {\mathbb C}$. If $H(\Omega)$ is endowed with its natural topology and $H(\Omega)^{\mathbb N}$ is endowed with…

Complex Variables · Mathematics 2026-03-11 L. Bernal-González , M. C. Calderón-Moreno , J. López-Salazar , J. A. Prado-Bassas

The moduli spaces of theta-semistable representations of a finite quiver can be packaged together to form a noncommutative compact manifold.

Algebraic Geometry · Mathematics 2016-09-07 Lieven Le Bruyn

Consider the self-map F of the space of real-valued test functions on the line which takes a test function f to the test function sending a real number x to f(f(x))-f(0). We show that F is discontinuous, although its restriction to the…

General Topology · Mathematics 2007-05-23 Helge Glockner

In this paper we consider the problem of characterization of topological spaces that embed into countably compact Hausdorff spaces. We study the separation axioms of subspaces of countably compact Hausdorff spaces and construct an example…

General Topology · Mathematics 2019-06-12 Taras Banakh , Serhii Bardyla , Alex Ravsky

A construction of product measures is given for an arbitrary sequence of measure spaces via outer measure techniques without imposing any condition on the underlying measure spaces. This approach concludes finally the problem of the…

Functional Analysis · Mathematics 2024-11-08 Juan Carlos Sampedro

We consider the space of real-valued continuously differentiable functions on a compact subset of a euclidean space. We characterize the completeness of this space and prove that the space of restrictions of continuously differentiable…

Classical Analysis and ODEs · Mathematics 2020-06-18 Leonhard Frerick , Laurent Loosveldt , Jochen Wengenroth

A topological space is nonseparably connected if it is connected but all of its connected separable subspaces are singletons. We show that each connected sequential topological space X is the image of a nonseparably connected complete…

General Topology · Mathematics 2011-10-11 T. Banakh , M. Vovk , M. R. Wójcik

We prove that for any compact zero-dimensional metric space $X$ on which an infinite countable amenable group $G$ acts freely by homeomorphisms, there exists a dynamical quasitiling with good covering, continuity, F{\o}lner and dynamical…

Dynamical Systems · Mathematics 2017-05-23 Tomasz Downarowicz , Dawid Huczek

We show that for arbitrary linearly ordered set $X$ any bounded family of (not necessarily, continuous) real valued functions on $X$ with bounded total variation does not contain independent sequences. We obtain generalized Helly's…

General Topology · Mathematics 2016-12-20 Michael Megrelishvili

Given based cellular spaces X and Y, X compact, we define a sequence of increasingly fine equivalences on the based-homotopy set [X,Y].

Algebraic Topology · Mathematics 2024-06-05 S. S. Podkorytov

Inspired by a recent work of Dias and Tall, we show that a compact indestructible space is sequentially compact. We also prove that a Lindelof Hausdorff indestructible space has the finite derived set property and a compact Hausdorff…

General Topology · Mathematics 2012-11-16 Angelo Bella