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We show that connected separable locally compact groups are infinitesimally finitely generated, meaning that there is an integer $n$ such that every neighborhood of the identity contains $n$ elements generating a dense subgroup. We…

Group Theory · Mathematics 2016-03-15 Tsachik Gelander , François Le Maître

We generalise Merzlyakov's theorem about the first-order theory of non-abelian free groups to all acylindrically hyperbolic groups. As a corollary, we deduce that if $G$ is an acylindrically hyperbolic group and $E(G)$ denotes the unique…

Group Theory · Mathematics 2022-03-09 Simon André , Jonathan Fruchter

Sets with a self-distributive operation (in the sense of $(a \triangleleft b) \triangleleft c = (a \triangleleft c) \triangleleft (b \triangleleft c))$, in particular quandles, appear in knot and braid theories, Hopf algebra classification,…

Group Theory · Mathematics 2025-11-26 Victoria Lebed , Arnaud Mortier

The study of the existence of free groups in skew linear groups have been begun since the last decades of the 20-th century. The starting point is the theorem of Tits (1972), now often is referred as Tits' Alternative, stating that every…

Rings and Algebras · Mathematics 2019-02-20 Bui Xuan Hai , Huynh Viet Khanh

We will show that every element of a finitely generated abelian group is automorphically equivalent what we will define to be a {\em representative element} in a {\em repeat-free subgroup}, and for finite abelian groups we can count the…

Group Theory · Mathematics 2011-09-12 Charles F. Rocca

Given an aleph_1-free abelian group G we characterize the class C_G of all torsion abelian groups T satisfying Ext(G,T)=0 assuming the continuum hypothesis CH. Moreover, in Godel's constructable universe we prove that this characterizes C_G…

Logic · Mathematics 2007-05-23 Saharon Shelah , Lutz Strüngmann

The authors investigate the structure of quasi-o-minimal groups. Among other results, they show that quasi-o-minimal groups are abelian, that quasi-o-minimal densely ordered archimedian groups are divisible, and that every divisible…

Rings and Algebras · Mathematics 2008-02-03 Oleg Belegradek , Ya'acov Peterzil , Frank Wagner

In this paper we bring together results about the density of subsemigroups of abelian Lie groups, the minimal number of topological generators of abelian Lie groups and a result about actions of algebraic groups. We find the minimal number…

Functional Analysis · Mathematics 2011-08-05 Herbert Abels , Antonios Manoussos

We show that just infinite quotients of finitely generated subgroups of Richard Thompson's group F are virtually abelian, answering a question of Grigorchuk. We show the same holds for the group of piecewise linear orientation preserving…

Group Theory · Mathematics 2025-03-19 Yash Lodha

In [11] Sklinos proved that any uncountable free group is not $\aleph_1$-homogenenous. This was later generalized by Belegradek in [1] to torsion-free residually finite relatively free groups, leaving open whether the assumption of residual…

Logic · Mathematics 2025-02-12 Davide Carolillo , Gianluca Paolini

In this article we study automorphisms of Toeplitz subshifts. Such groups are abelian and any finitely generated torsion subgroup is finite and cyclic. When the complexity is non superlinear, we prove that the automorphism group is, modulo…

Dynamical Systems · Mathematics 2017-06-15 Sebastián Donoso , Fabien Durand , Alejandro Maass , Samuel Petite

We give new and improved results on the freeness of subgroups of free profinite groups: A subgroup containing the normal closure of a finite word in the elements of a basis is free; Every infinite index subgroup of a finitely generated…

Group Theory · Mathematics 2017-05-17 Mark Shusterman

Let $\operatorname{TFAb}_r$ be the class of torsion-free abelian groups of rank $r$, and let $\operatorname{FD}_r$ be the class of fields of characteristic $0$ and transcendence degree~$r$. We compare these classes using various notions.…

Logic · Mathematics 2024-03-20 Meng-Che "Turbo" Ho , Julia Knight , Russell Miller

A classical problem, raised by Fuchs in 1960, asks to classify the abelian groups which are groups of units of some rings. In this paper, we consider the case of finitely generated abelian groups, solving Fuchs' problem for such group with…

Commutative Algebra · Mathematics 2024-06-04 I. Del Corso , L. Stefanello

In the recent paper by A. A. Klyachko, V. Yu. Miroshnichenko, and A. Yu. Olshanskii, it is proven that the center of any finite strongly verbally closed group is its direct factor. One of the results of the current paper is the…

Group Theory · Mathematics 2024-02-16 Filipp D. Denissov

Birman-Lubotzky-McCarthy proved that any abelian subgroup of the mapping class groups for orientable surfaces is finitely generated. We apply Birman-Lubotzky-McCarthy's arguments to the mapping class groups for non-orientable surfaces. We…

Geometric Topology · Mathematics 2021-07-27 Erika Kuno

We show that if $G$ is a non-elementary word hyperbolic group, mapping class group of a hyperbolic surface or the outer automorphism group of a nonabelian free group then $G$ has $2^{\aleph_0}$ many continuous ergodic invariant random…

Group Theory · Mathematics 2015-06-02 Lewis Bowen , Rostislav Grigorchuk , Rostyslav Kravchenko

Bestvina, Feighn and Handel proved that every subgroup of the outer automorphism group, $\textrm{Out}(F_n)$, of the free group of rank $n$ is either virtually finitely generated abelian or contains a nonabelian free group. In this note we…

Group Theory · Mathematics 2022-03-22 Ioannis Papavasileiou , Mihalis Sykiotis

Continuing recent studies of both the hereditary and super properties of certain classes of Abelian groups, we explore in-depth what is the situation in the quite large class consisting of directly finite Abelian groups. Trying to connect…

Group Theory · Mathematics 2025-03-17 Peter Danchev , Brendan Goldsmith , Fatemeh Karimi

We construct finitely generated simple torsion-free groups with strong homological control. Our main result is that every subset of $\mathbb{N} \cup \{\infty\}$, with some obvious exceptions, can be realized as the set of dimensions of…

Group Theory · Mathematics 2025-04-14 Francesco Fournier-Facio , Bin Sun