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We show that the topological full group of a Hausdorff ample groupoid with compact unit space coincides with the group of homotopy classes of invertible isometries in pseudofunction algebras associated with the groupoid. Moreover, if the…

Operator Algebras · Mathematics 2025-11-19 Eusebio Gardella , Mathias Palmstrøm , Hannes Thiel

It is a well known result in the covering groups that a subgroup $G$ of the fundamental group at the identity of a semi-locally simply connected topological group determines a covering morphism of topological groups with characteristic…

Algebraic Topology · Mathematics 2016-01-27 Osman Mucuk , Tunçar Şahan

In this paper we study the topology of the cobordism category of open and closed strings. This is a 2-category in which the objects are compact one-manifolds whose boundary components are labeled by an indexing set (the set of "D-branes"),…

Algebraic Topology · Mathematics 2007-05-23 Nils A. Baas , Ralph L. Cohen , Antonio Ramirez

A class of almost paratopological groups is introduced, which (1) contains paratopological groups and Hausdorff quasitopological groups; (2) is closed under products; (3) subgroups. Almost paratopological $T_1$ groups $G$ are characterized…

General Topology · Mathematics 2023-08-22 Evgenii Reznichenko

We study topological group theoretic properties of algebraic groups over local fields. In particular, we find conditions under which such groups have closed images under arbitrary continuous homomorphisms into arbitrary topological groups.

Group Theory · Mathematics 2023-01-04 Uri Bader , Elyasheev Leibtag

Let $\mathcal K$ be a complete quasivariety of completely regular universal topological algebras of continuous signature $\mathcal E$ (which means that $\mathcal K$ is closed under taking subalgebras, Cartesian products, and includes all…

General Topology · Mathematics 2012-02-22 T. Banakh , O. Hryniv

A topologized semilattice $X$ is called complete if each non-empty chain $C\subset X$ has $\inf C$ and $\sup C$ that belong to the closure $C$ of the chain $C$ in $X$. In this paper, we introduce various concepts of completeness of…

Rings and Algebras · Mathematics 2021-08-19 Konstantin Kazachenko , Alexander V. Osipov

We show that $C(X)$ admits an equivalent pointwise lower semicontinuous locally uniformly rotund norm provided $X$ is Fedorchuk compact of spectral height 3. In other words $X$ admits a fully closed map $f$ onto a metric compact $Y$ such…

Functional Analysis · Mathematics 2018-11-26 S. P. Gul'ko , A. V. Ivanov , M. S. Shulikina , S. Troyanski

The article is devoted to a structure of topological spaces related with topological quasigroups. Regular and complete spaces over topological quasigroups are studied. Separations and embeddings are also investigated for them. Their…

Group Theory · Mathematics 2023-12-29 S. V. Ludkowski

In this paper we establish a connection between categorical closedness and topologizability of semigroups. In particular, for a class $\mathsf T_{\!1}\mathsf S$ of $T_1$ topological semigroups we prove that a countable semigroup $X$ with…

General Topology · Mathematics 2022-12-27 Taras Banakh , Serhii Bardyla

In the paper we present various characterizations of chain-compact and chain-finite topological semilattices. A topological semilattice $X$ is called chain-compact (resp. chain-finite) if each closed chain in $X$ is compact (finite). In…

General Topology · Mathematics 2021-11-02 Taras Banakh , Serhii Bardyla

We study topologization of the semigroup $\mathscr{O\!\!I}\!_n(L)$ of finite partial order isomorphisms of a bounded rank of an infinite linear ordered set $(L,\leqslant)$. In particular we show that every $T_1$ left-topological…

Group Theory · Mathematics 2025-12-01 Oleg Gutik , Maksym Shchypel

A group $G$ is called hereditarily non-topologizable if, for every $H\le G$, no quotient of $H$ admits a non-discrete Hausdorff topology. We construct first examples of infinite hereditarily non-topologizable groups. This allows us to prove…

Group Theory · Mathematics 2013-10-02 A. A. Klyachko , A. Yu. Olshanskii , D. V. Osin

In this paper we give conditions under which a topological semigroup can be embedded algebraically and topologically into a compact topological group. We prove that every feebly compact regular first countable cancellative commutative…

General Topology · Mathematics 2020-06-16 Julio César Hernández Arzusa

For separable $C^*$-algebras $A$ and $B$, we define a topology on the set $[[A, B]]$ consisting of homotopy classes of asymptotic morphisms from $A$ to $B$. This gives an enrichment of the Connes--Higson asymptotic category over topological…

Operator Algebras · Mathematics 2024-10-21 José R. Carrión , Christopher Schafhauser

For r at least 3, p at least 2, we classify all actions of the groups Diff^r_c(R) and Diff^r_+(S1) by C^p -diffeomorphisms on the line and on the circle. This is the same as describing all nontrivial group homomorphisms between groups of…

Geometric Topology · Mathematics 2013-09-10 Kathryn Mann

A Hausdorff topological group is called minimal if it does not admit a strictly coarser Hausdorff group topology. This paper mostly deals with the topological group $H_+(X)$ of order-preserving homeomorphisms of a compact linearly ordered…

General Topology · Mathematics 2015-06-19 Michael Megrelishvili , Luie Polev

We embed a countably categorical group G into a locally compact group c(G) with a non-trivial topology and study how topological properties of c(G) are connected with the structure of definable subgroups of G.

Logic · Mathematics 2008-11-04 Al. A. Ivanov

Let $S$ be a semigroup (written multiplicatively). Endowed with the operation of setwise multiplication induced by $S$ on its parts, the non-empty subsets of $S$ form themselves a semigroup, denoted by $\mathcal P(S)$. Accordingly, we say…

Rings and Algebras · Mathematics 2025-10-02 Lingxi Li , Salvatore Tringali

A convenient bicategory of topological stacks is constructed which is both complete and Cartesian closed. This bicategory, called the bicategory of compactly generated stacks, is the analogue of classical topological stacks, but for a…

Algebraic Topology · Mathematics 2016-10-18 David Carchedi