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In the present paper, homeomorphisms in metric spaces which generalize quasiconformal mappings, are investigated. It is proved that, at some conditions on metric spaces and boundaries of corresponding domains, families of above mappings are…

Metric Geometry · Mathematics 2017-10-10 Evgeny Sevost'yanov

We show that every orientation-preserving circle homeomorphism is a composition of two conformal welding homeomorphisms, which implies that conformal welding homeomorphisms are not closed under composition. Our approach uses the…

Complex Variables · Mathematics 2025-02-18 Alex Rodriguez

For each countable ordinal $\alpha$, we introduce an ideal $conv_\alpha$ and use it to characterize the class of all compact countable spaces which are homeomorphic to the space $\omega^{\alpha}\cdot n+1$ with the order topology. The…

General Topology · Mathematics 2025-03-18 Rafał Filipów , Małgorzata Kowalczuk , Adam Kwela

The notion of a complete Boolean algebra, although completely legitimate in constructive mathematics, fails to capture some natural structures such as the lattice of subsets of a given set. Sambin's notion of an overlap algebra, although…

Logic in Computer Science · Computer Science 2023-06-22 Francesco Ciraulo , Michele Contente

We prove that the homeomorphism problem for connected compact metric spaces is Borel bireducible with a universal orbit equivalence relation induced by a Borel action of a Polish group.

Logic · Mathematics 2016-04-13 Cheng Chang , Su Gao

All spaces are assumed to be separable and metrizable. We show that, assuming the Axiom of Determinacy, every zero-dimensional homogeneous space is strongly homogeneous (that is, all its non-empty clopen subspaces are homeomorphic), with…

General Topology · Mathematics 2020-03-03 Raphaël Carroy , Andrea Medini , Sandra Müller

We study the topology of some simple infinite dimensional singularities arising from spaces of \emph{algebraic formal loops}. We prove that in some simple cases the natural analogue of nearby cycles cohomology for a function on the loop…

Algebraic Geometry · Mathematics 2022-02-15 Emile Bouaziz

A topological monoid is isomorphic to an endomorphism monoid of a countable structure if and only if it is separable and has a compatible complete ultrametric such that composition from the left is non-expansive. We also give a topological…

Logic · Mathematics 2018-10-16 Manuel Bodirsky , Friedrich Martin Schneider

We define a notion of (one-sided) edge shift spaces associated to ultragraphs. In the finite case our notion coincides with the edge shift space of a graph. In general, we show that our space is metrizable and has a countable basis of…

Operator Algebras · Mathematics 2017-05-19 Daniel Gonçalves , Danilo Royer

We introduce the notion of spaces with weak relative cohomology and show the acyclicity of the complement $Q\setminus X$ in the Hilbert cube $Q$ of a compactum $X$ with weak relative cohomology. As a corollary we obtain the acyclicity of…

General Topology · Mathematics 2016-03-23 Ashwini Amarasinghe , Alexander Dranishnikov

We show that a homotopy equivalence between compact, connected, oriented surfaces with non-empty boundary is homotopic to a homeomorphism if and only if it commutes with the Goldman bracket.

Geometric Topology · Mathematics 2011-11-08 Siddhartha Gadgil

We introduce a notion of graph homeomorphisms which uses the concept of dimension and homotopy for graphs. It preserves the dimension of a subbasis, cohomology and Euler characteristic. Connectivity and homotopy look as in classical…

General Topology · Mathematics 2014-01-14 Oliver Knill

Here we classify all topological spaces where all bijections to itself are homeomorphisms. As a consequence, we also classify all topological spaces where all maps to itself are continuous. Analogously, we classify all measurable spaces…

General Topology · Mathematics 2024-01-10 Lucas H. R. de Souza

Let X be an infinite compact metric space with finite covering dimension. Let $\afhpa,\bt: X\to X$ be two minimal homeomorphisms. Suppose that the range of $K_0$-groups of both crossed product C*-algebras s are dense in the space of real…

Operator Algebras · Mathematics 2007-05-23 Huaxin Lin

Under the assumption of the gluing orbit property, equivalent conditions to having zero topological entropy are investigated. In particular, we show that a dynamical system has the gluing orbit property and zero topological entropy if and…

Dynamical Systems · Mathematics 2020-07-03 Peng Sun

Recall that the Rado graph is the unique countable graph that realizes all one-point extensions of its finite subgraphs. The Rado graph is well-known to be universal and homogeneous in the sense that every isomorphism between finite…

Logic · Mathematics 2018-07-17 Jan Grebík

Consider the semialgebraic structure over the real field. More generally, let an ominimal structure be over a real closed field. We show that a definable metric space X with a definable metric d is embedded into a Euclidean space so that…

Algebraic Geometry · Mathematics 2017-08-31 Masahiro Shiota

The dual complex of a singularity is defined, up-to homotopy, using resolutions of singularities. In many cases, for instance for isolated singularities, we identify and study a "minimal" representative of the homotopy class that is well…

Algebraic Geometry · Mathematics 2014-03-18 Tommaso de Fernex , János Kollár , Chenyang Xu

A structure is called homogeneous if every isomorphism between finite substructures of the structure extends to an automorphism of the structure. Recently, P. J. Cameron and J. Ne\v{s}et\v{r}il introduced a relaxed version of homogeneity:…

Combinatorics · Mathematics 2010-01-06 Dragan Mašulović , Rajko Nenadov , Nemanja Škorić

In this paper we prove that the homeomorphism relation of locally connected continua is a complete orbit equivalence relation. This answers a question posed by Chang and Gao.

Logic · Mathematics 2018-01-26 Tomasz Cieśla