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We show that every countable group H with solvable word problem (=computable group) can be subnormally embedded into a 2-generated group G which also has solvable word problem. Moreover, the membership problem for H < G is also solvable. We…

Group Theory · Mathematics 2017-08-16 Arman Darbinyan

We summarize several results about non-simplicity, solvability and normal structure of finite groups related to the number of conjugacy classes appearing in the product or the power of conjugacy classes. We also collect some problems that…

Group Theory · Mathematics 2024-02-14 Antonio Beltrán , María José Felipe , Carmen Melchor

We introduce a class of countable groups by some abstract group-theoretic conditions. It includes linear groups with finite amenable radical and finitely generated residually finite groups with some non-vanishing $\ell^2$-Betti numbers that…

Group Theory · Mathematics 2018-07-20 Uri Bader , Alex Furman , Roman Sauer

An algorithm is constructed that, when given an explicit presentation of a finitely generated nilpotent group $G,$ decides for any pair of endomorphisms $\varphi, \psi : G \to G$ and any pair of elements $u, v \in G,$ whether or not the…

Group Theory · Mathematics 2009-10-20 V. Roman'kov , E. Ventura

Let $G$ be a group. Then $S\subseteq G$ is an invariable generating set of $G$ if every subset $S'$ obtained from $S$ by replacing each element with a conjugate is also a generating set of $G$. We investigate invariable generation among key…

Group Theory · Mathematics 2025-05-29 Charles Garnet Cox , Anitha Thillaisundaram

We study a family of groups consisting of the simplest extensions of lamplighter groups. We use these groups to answer multiple open questions in combinatorial group theory, providing groups that exhibit various combinations of properties:…

Group Theory · Mathematics 2025-07-21 Corentin Bodart

We study the conjugacy problem in cyclic extensions of free groups. It is shown that the conjugacy problem is solvable in split extensions of finitely generated free groups by virtually inner automorphisms. An algorithm for construction of…

Group Theory · Mathematics 2007-05-23 Valerij Bardakov , Leonid Bokut , Andrei Vesnin

We construct a finitely presented (two-sided) totally orderable group with insoluble word problem.

Group Theory · Mathematics 2014-02-26 V. V. Bludov , A. M. W. Glass

Let $\Gamma$ be a finitely generated cocompact lattice of a totally disconnected locally compact group $G$, and $C$ a dense subgroup of $G$ that contains and commensurates $\Gamma$. We study the problem of describing all finitely generated…

Group Theory · Mathematics 2026-04-08 Adrien Le Boudec , Colin Reid

We prove for residually finite groups the following long standing conjecture: the number of twisted conjugacy classes of an automorphism of a finitely generated group is equal (if it is finite) to the number of finite dimensional…

Group Theory · Mathematics 2012-05-01 Alexander Fel'shtyn , Evgenij Troitsky

We prove that, for a finitely generated residually finite group, having solvable word problem is not a sufficient condition to be a subgroup of a finitely presented residually finite group. The obstruction is given by a residually finite…

Group Theory · Mathematics 2021-03-19 Emmanuel Rauzy

We prove that there exist finitely presented, residually finite groups that are profinitely rigid in the class of all finitely presented groups but not in the class of all finitely generated groups. These groups are of the form $\Gamma…

Group Theory · Mathematics 2025-04-15 M. R. Bridson , A. W. Reid , R. Spitler

We prove that the isomorphism problem for finitely generated fully residually free groups is decidable. We also show that each finitely generated fully residually free group G has a decomposition that is invariant under automorphisms of G,…

Group Theory · Mathematics 2007-05-23 Inna Bumagin , Olga Kharlampovich , Alexei Miasnikov

We consider pairs of finitely presented, residually finite groups $P\hookrightarrow\G$ for which the induced map of profinite completions $\hat P\to \hat\G$ is an isomorphism. We prove that there is no algorithm that, given an arbitrary…

Group Theory · Mathematics 2008-10-03 Martin R. Bridson

We prove that, for every integer $n \ge 2$, a finite or infinite countable group $G$ can be embedded into a 2-generated group $H$ in such a way that the solvability of quadratic equations of length at most $n$ is preserved, i.e., every…

Group Theory · Mathematics 2016-07-25 Desmond F. Cummins , Sergei V. Ivanov

This article presents the construction of finitely generated branch groups with uncountably many maximal subgroups using embedding techniques. This addresses a question posed by Grigorchuk.

Group Theory · Mathematics 2025-09-12 J. Moritz Petschick

Given a finite group $G$, the generating graph $\Gamma(G)$ of $G$ has as vertices the non-identity elements of $G$ and two vertices are adjacent if and only if they are distinct and generate $G$ as group elements. Let $G$ be a 2-generated…

Group Theory · Mathematics 2019-08-06 Andrea Lucchini

In this paper we introduce the graph $\Gamma_{sc}(G)$ associated with a group $G$, called the solvable conjugacy class graph (abbreviated as SCC-graph), whose vertices are the nontrivial conjugacy classes of $G$ and two distinct conjugacy…

Combinatorics · Mathematics 2022-02-08 Parthajit Bhowal , Peter J. Cameron , Rajat Kanti Nath , Benjamin Sambale

We prove that every finitely generated group $G$ discriminated by a locally quasi-convex torsion-free hyperbolic group $\Gamma$ is effectively coherent: that is, presentations for finitely generated subgroups can be computed from the…

Group Theory · Mathematics 2014-12-12 Inna Bumagin , Jeremy Macdonald

We establish several results on the word problem for just infinite groups. First, for finitely generated just infinite groups we show that the word problem is uniformly decidable for presentations with recursively enumerable sets of…

Group Theory · Mathematics 2026-03-30 Alexey Talambutsa