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Related papers: Free non-archimedean topological groups

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We use topological methods to study the maximal subgroups of the free idempotent generated semigroup on a biordered set. We use these to give an example of a free idempotent generated semigroup with maximal subgroup isomorphic to the free…

Group Theory · Mathematics 2008-08-14 Mark Brittenham , Stuart W. Margolis , John Meakin

Let $G$ be a hyperbolic group that splits as a graph of free groups with cyclic edge groups. We prove that, unless $G$ is isomorphic to a free product of free and surface groups, every finite abelian group $M$ appears as a direct summand in…

Group Theory · Mathematics 2025-05-28 Dario Ascari , Jonathan Fruchter

The topological fundamental group $\pi_{1}^{top}$ is a homotopy invariant finer than the usual fundamental group. It assigns to each space a quasitopological group and is discrete on spaces which admit universal covers. For an arbitrary…

Algebraic Topology · Mathematics 2020-04-14 Jeremy Brazas

We prove that, if a topological group $G$ has an open subgroup of infinite index, then every net of tight Borel probability measures on $G$ UEB-converging to invariance dissipates in $G$ in the sense of Gromov. In particular, this solves a…

Metric Geometry · Mathematics 2020-01-22 Friedrich Martin Schneider

A topological space is called {\it dense-separable} if each dense subset of its is separable. Therefore, each dense-separable space is separable. We establish some basic properties of dense-separable topological groups. We prove that each…

General Topology · Mathematics 2022-12-27 Fucai Lin , Qiyun Wu , Chuan Liu

The explicit description of the topology of the free product of topological groups being Hausdorff is given. In particular, it is shown that it coincides with the so-called $X_0$-topology for the corresponding colimit $X$ in the category of…

General Topology · Mathematics 2019-05-03 G. Samsonadze , D. Zangurashvili

An uncountable $\aleph_1$-free group cannot admit a Polish group topology but an uncountable $\aleph_1$-free abelian group can, as witnessed, for example, by the Baer-Specker group $\mathbb{Z}^\omega$; more strongly, $\mathbb{Z}^\omega$ is…

Logic · Mathematics 2026-03-30 Gianluca Paolini , Saharon Shelah

We prove group existence and structure theorems in a general setting of tame topological theories. More precisely, we identify a linear/non-linear dividing line -- called topological 1-basedness -- among the class of t-minimal theories with…

Logic · Mathematics 2025-08-27 Benjamin Castle , Assaf Hasson , Will Johnson

Research on topological phases of matter is a core field in modern condensed matter physics. Free fermion systems, such as topological insulators and superconductors, have been studied using the "Tenfold Way" and K-theory. Building on…

Mesoscale and Nanoscale Physics · Physics 2026-05-13 Tian Yuan , Yang Qi

We derive many upper bounds on the submetrizability number and $i$-weight of paratopological groups and topological monoids with open shifts. In particular, we prove that each first countable Hausdorff paratopological group is submetrizable…

General Topology · Mathematics 2016-02-19 Taras Banakh , Alex Ravsky

We give a construction of two-sided invariant metrics on free products (possibly with amalgamation) of groups with two-sided invariant metrics and, under certain conditions, on HNN extensions of such groups. Our approach is similar to the…

Logic · Mathematics 2013-03-19 Konstantin Slutsky

We give a topological interpretation of the free metabelian group, following the plan described in [Ver1,Ver2]. This interpretation is based on considering the Caley graph of a finitely generated group G as one-dimensional complex; its…

Group Theory · Mathematics 2007-05-23 A. Vershik , S. Dobrynin

Topological properties of the free topological group and the free abelian topological group on a space have been thoroughly studied since the 1940s. In this paper, we study the free topological $\mathbb{R}$-vector space $V(X)$ on $X$. We…

General Topology · Mathematics 2021-07-23 Rafael Dahmen , Gábor Lukács

In this paper we characterize [strict] o-boundedness of the free (abelian) topological group F(X) (A(X)) as well as the free locally-convex linear topological space L(X) in terms of properties of a Tychonoff space X. These properties appear…

General Topology · Mathematics 2007-05-23 Lyubomyr Zdomskyy

V. G. Pestov described a neighborhood base at the identity of the Markov free topological group $F(X)$ on a Tychonoff space $X$ in terms of the fine uniformity on $X$. In this paper, an analogue of Pestov's description for the Markov free…

General Topology · Mathematics 2013-03-19 Ali Sayed Elfard

We show that every non-precompact topological group admits a fixed point-free continuous action by affine isometries on a suitable Banach space. Thus, precompact groups are defined by the fixed point property for affine isometric actions on…

Group Theory · Mathematics 2008-11-06 Lionel Nguyen Van Thé , Vladimir G. Pestov

In this paper, we first study the endomorphisms of free-abelian times surface groups and give a characterization of when they are injective and surjective. Then, we see that free-abelian times hyperbolic groups are Hopfian but not…

Group Theory · Mathematics 2025-11-18 Ke Wang , Qiang Zhang , Dongxiao Zhao

For a countable abelian group $G$ we investigate generic properties of the space of all invariant metrics on $G$. We prove that for every such an unbounded group $G$, i.e. group which has elements of arbitrarily high order, there is a dense…

General Topology · Mathematics 2019-02-28 Michal Doucha

A topological space $X$ is defined to have a neighborhood $P$-base at any $x\in X$ from some poset $P$ if there exists a neighborhood base $(U_p[x])_{p\in P}$ at $x$ such that $U_p[x]\subseteq U_{p'}[x]$ for all $p\geq p'$ in $P$. We prove…

General Topology · Mathematics 2021-05-21 Ziqn Feng

Given a topological group $G$ that can be embedded as a topological subgroup into some topological vector space (over the field of reals) we say that $G$ has invariant linear span if all linear spans of $G$ under arbitrary embeddings into…

General Topology · Mathematics 2020-07-23 Eva Pernecká , Jan Spěvák