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We show that all finitely generated free-by-cyclic groups are conjugacy separable: if a finitely generated group $G$ surjects onto $\mathbb{Z}$ with free kernel, then for every pair of non-conjugate elements $g,h\in G$, there exists a…

Group Theory · Mathematics 2026-04-22 François Dahmani , Sam Hughes , Monika Kudlinska , Nicholas Touikan

We introduce moment maps for continuous unitary representations of general topological groups. For solvable separable locally compact groups, we prove that the closure of the image of the moment map of any representation is convex.

Representation Theory · Mathematics 2014-08-21 Daniel Beltita , Mihai Nicolae

Various characterizations of finite convex geometries are well known. This note provides similar characterizations for possibly infinite convex geometries whose lattice of closed sets is strongly coatomic and lower continuous. Some classes…

Combinatorics · Mathematics 2017-01-27 Kira Adaricheva , J. B. Nation

In this paper we survey a new criteria for solvability of finite groups in terms of number of supersolvable (also known as polycyclic) and non-supersolvable subgroups. In particular, we present original examples of supersolvable groups such…

General Mathematics · Mathematics 2022-08-29 Primitivo B. Acosta-Humánez , Orieta Liriano , Francis Mora-Ferreras

For a given variety of groups $\X$, we develop a systematic theory of $\CSX$-groups and $\XT$-groups, extending ideas proposed in \cite{Shah}. We analyze the interplay between these classes, describe their structural properties, and examine…

Group Theory · Mathematics 2026-01-05 Omar Al-Raisi , Mohammad Shahryari

Periodic and quasi-periodic orbits of the $n$-body problem are critical points of the action functional constrained to the Sobolev space of symmetric loops. Variational methods yield collisionless orbits provided the group of symmetries…

Dynamical Systems · Mathematics 2007-05-23 Davide L. Ferrario

Assuming that every hyperbolic group is residually finite, we prove the congruence subgroup property for mapping class groups of hyperbolic surfaces of finite type. Under the same assumption, it follows that profinitely equivalent…

Group Theory · Mathematics 2024-11-26 Henry Wilton , Alessandro Sisto

We find a condition on the underlying graph of an Artin group that fully determines if it is subgroup separable. As a consequence, an Artin group is subgroup separable if and only if it can be obtained from Artin groups of ranks at most 2…

Group Theory · Mathematics 2021-05-10 Kisnney Almeida , Igor Lima

In this paper we prove that groups as in the title are convex cocompact in the mapping class group.

Geometric Topology · Mathematics 2017-11-21 Mladen Bestvina , Kenneth Bromberg , Richard P. Kent , Christopher J. Leininger

We show that certain graphs of groups with cyclic edge groups are aTmenable. In particular, this holds when each vertex group is either virtually special or acts properly and semisimply on $\mathbb{H}^n$.

Group Theory · Mathematics 2017-01-03 Mathieu Carette , Daniel T. Wise , Daniel J. Woodhouse

A JSJ-splitting of a group $G$ over a certain class of subgroups is a graph of groups decomposition of $G$ which describes all possible decompositions of $G$ as an amalgamated product or an HNN extension over subgroups lying in the given…

Group Theory · Mathematics 2007-05-23 Koji Fujiwara , Panos Papasoglu

In this expository article, we give a self-contained introduction to the wonderfully well-behaved class of pseudocompact algebras, focusing on the foundational classes of semisimple and separable algebras. We give characterizations of such…

Rings and Algebras · Mathematics 2025-01-20 Kostiantyn Iusenko , John MacQuarrie

Let M be a surface (possibly nonorientable) with punctures and/or boundary components. The paper is a study of ``geometric subgroups'' of the mapping class group of M, that is subgroups corresponding to inclusions of subsurfaces (possibly…

Geometric Topology · Mathematics 2014-02-18 Michal Stukow

We prove that every free metabelian non--cyclic group has a finitely generated isolated subgroup which is not separable in the class of nilpotent groups. As a corollary we prove that for every prime number $p$ an arbitrary free metabelian…

Group Theory · Mathematics 2007-05-23 Valerij G. Bardakov

We discuss a number of open problems about mapping class groups of surfaces. In particular, we discuss problems related to linearity, congruence subgroups, cohomology, pseudo-Anosov stretch factors, Torelli subgroups, and normal subgroups.

Geometric Topology · Mathematics 2018-06-25 Dan Margalit

It is shown that a closed solvable subgroup of a connected Lie group is compactly generated. In particular, every discrete solvable subgroup of a connected Lie group is finitely generated. Generalizations to locally compact groups are…

Group Theory · Mathematics 2011-02-19 Karl Heinrich Hofmann , Karl-Hermann Neeb

A group $G$ is called subgroup conjugacy separable if for every pair of non-conjugate finitely generated subgroups of $G$, there exists a finite quotient of $G$ where the images of these subgroups are not conjugate. It is proved that the…

Group Theory · Mathematics 2016-05-31 S. C. Chagas , P. A. Zalesskii

We construct a boundary of a finite rank free group relative to a finite list of conjugacy classes of maximal cyclic subgroups. From the cut points and uncrossed cut pairs of this boundary we construct a simplicial tree on which the group…

Group Theory · Mathematics 2016-05-04 Christopher H. Cashen

In this paper we show that for every congruent monotileable amenable group $G$ and for every metrizable Choquet simplex $K$, there exists a minimal $G$-subshift, which is free on a full measure set, whose set of invariant probability…

Dynamical Systems · Mathematics 2017-09-26 Paulina Cecchi , María Isabel Cortez

Let G be the free product of groups A and B with commuting subgroups H \leqslant A and K \leqslant B, and let C be the class of all finite groups or the class of all finite p-groups. We derive the description of all C-separable cyclic…

Group Theory · Mathematics 2013-08-12 E. V. Sokolov