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Related papers: A note on localizations of perfect groups

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Examples are given of profinite groups that are not strongly complete, and have other `bad' properties, yet have only finitely many open subgroups of each finite index. It is shown that a profinite group with the latter property must be…

Group Theory · Mathematics 2021-03-31 Dan Segal

We prove that localization functors of crossed modules of groups do not always admit fiberwise (or relative) versions. To do so we characterize the existence of a fiberwise localization by a certain normality condition and compute explicit…

Category Theory · Mathematics 2022-10-31 Olivia Monjon , Jérôme Scherer , Florence Sterck

We prove that a large class of metrizable group topologies for subgroups of $\mathbb{R}^n$ and the completions of the subgroups are locally isometric to, respectively, metrizable group topologies for $\mathbb{Z}$ and their completions,…

General Topology · Mathematics 2007-05-23 Jon W. Short

We provide a unified treatment of several results concerning full groups of ample groupoids and paradoxical decompositions attached to them. This includes a criterion for the full group of an ample groupoid being amenable as well as…

Operator Algebras · Mathematics 2026-04-28 Vadim Alekseev , Martin Finn-Sell

In this article, we characterize the distortion elements of the group of smooth diffeomorphisms of the circle and of the group of compactly supported smooth diffeomorphisms of the real line. More precisely, we prove that, in this context,…

Dynamical Systems · Mathematics 2025-07-21 Hélène Eynard-Bontemps , Emmanuel Militon

Topological full groups originated from the theory of topological dynamical systems and have been having considerable impact on group theory in recent years. This text represents an introduction/survey on topological full groups. After…

Group Theory · Mathematics 2019-07-19 Leonhard Katzlinger

We define a `nice representation' of a finitely presented group G as being a non-degenerate essentially surjective simplicial map f from a `nice' space X into a 3-complex associated to a presentation of G, with a strong control over the…

Geometric Topology · Mathematics 2016-03-22 Daniele Ettore Otera , Valentin Poenaru

An $integral$ of a group $G$ is a group $H$ whose derived group (commutator subgroup) is isomorphic to $G$. This paper discusses integrals of groups, and in particular questions about which groups have integrals and how big or small those…

Group Theory · Mathematics 2018-08-24 João Araújo , Peter J. Cameron , Carlo Casolo , Francesco Matucci

We construct classifying spaces for discrete and compact Lie groups, with the property that they are topological groups and complete metric spaces in a natural way. We sketch a program in view of extending these constructions.

Algebraic Topology · Mathematics 2017-02-08 Ivan Marin

We characterize the groups isomorphic to full automorphism groups of ordered abelian groups. The result will follow from classical theorems on ordered groups adding an argument from proofs used to realize rings as endomorphism rings of…

Logic · Mathematics 2007-05-23 Rüdiger Göbel , Saharon Shelah

The purpose of this note is to describe a space that is regular but not completely regular, but only barely so: all closed sets are $G_\delta$-sets and every singleton is a zero-set.

General Topology · Mathematics 2025-08-20 Klaas Pieter Hart

We define a numerical quasi-isometry invariant of a finitely generated group, whose values parametrize the difference between the group being uniformly embeddable in a Hilbert space and the reduced C*-algebra of the group being exact.

Operator Algebras · Mathematics 2007-05-23 Erik Guentner , Jerome Kaminker

A Polish group is said to be locally Roelcke precompact if there is a neighborhood of the identity element that is totally bounded in the Roelcke (or lower) group uniformity. These form a subclass of the locally bounded groups, while…

Group Theory · Mathematics 2018-06-12 Joseph Zielinski

A characterization of congruences in free semigroups is presented.

General Mathematics · Mathematics 2008-10-20 Elemer E Rosinger

Our purpose is to visualize the pronilpotent completion of a finitely generated free group as a certain subgroup in the free Lie group.

Group Theory · Mathematics 2025-08-13 Yury A. Neretin

We describe structure of locally finite groups of finite centraliser dimension.

Group Theory · Mathematics 2019-01-31 Alexandre Borovik , Ulla Karhumäki

We make a list of finite simple groups whose group rings over a given field are serial.

Rings and Algebras · Mathematics 2017-01-16 Andrei Kukharev , Gena Puninski

We study cyclically presented groups of type $\mathfrak{F}$ to determine when they are perfect. It turns out that to do so, it is enough to consider the Prishchepov groups, so modulo a certain conjecture, we classify the perfect Prishchepov…

Group Theory · Mathematics 2021-10-22 Ihechukwu Chinyere , Bernard Oduoku Bainson

It is proven that the identity component of the group preserving the leaves of a generalized foliation is perfect. This shows that a well-known simplicity theorem on the diffeomorphism group extends to the nontransitive case.

Differential Geometry · Mathematics 2007-05-23 Stefan Haller , Tomasz Rybicki

We construct long sequences of localization functors L_a in the category of abelian groups such that L_a > L_b for infinite cardinals a < b less than some k. For sufficiently large free abelian groups F and a < b we have proper inclusions…

Group Theory · Mathematics 2009-12-04 Adam J. Przezdziecki