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Related papers: A new family of sofic one-relator groups

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We give a construction of a family of locally finite residually finite groups with just-infinite C*-algebra. This answers a question from [2]. Additionally, we show that residually finite groups of finite exponent are never just-infinite.

Operator Algebras · Mathematics 2016-06-27 V. Belyaev , R. Grigorchuk , P. Shumyatsky

We prove that every {finitely generated residually finite}-by-sofic group satisfies Kaplansky's direct and stable finiteness conjectures with respect to all noetherian rings. We use this result to provide countably many new examples of…

Group Theory · Mathematics 2015-01-14 Federico Berlai

We show that the intersection of the rational derived series of a one-relator group is rationally perfect and is normally generated by a single element. As a corollary, we characterise precisely when a one-relator group is residually…

Group Theory · Mathematics 2025-09-22 Marco Linton

We present two uncountable families of finitely generated residually finite groups all having the same profinite completion. One consists of soluble groups, the other of branch groups.

Group Theory · Mathematics 2021-07-30 Nikolay Nikolov , Dan Segal

This communication records some observations made in the course of studying one-relator groups from the point of view of residual solvability. As a contribution to clas- sification efforts we single out some relator types that render the…

Group Theory · Mathematics 2013-10-22 Delaram Kahrobaei , Andrew F. Douglas , Katalin Bencsáth

We construct an uncountable family of periodic locally soluble groups which are hereditarily just infinite. We also show that the associated full C*-algebra C*(G) is just infinite for many groups $G$ in this family.

Group Theory · Mathematics 2017-03-24 Rostislav Grigorchuk , Pavel Shumyatsky

Answering some queries of Weiss, we prove that the free product and amenable extensions of sofic groups are sofic as well, and give an example of a finitely generated sofic group that is not residually amenable.

Group Theory · Mathematics 2007-05-23 G. Elek , E. Szabo

We exhibit a family of infinite, finitely-presented, nilpotent-by-abelian groups. Each member of this family is a solvable S-arithmetic group that is related to Baumslag-Solitar groups, and everyone of these groups has a quasi-isometry…

Group Theory · Mathematics 2007-05-23 Kevin Wortman

In 2005, Borisov and Sapir proved that ascending HNN extensions of finitely generated linear groups are residually finite. Subsequently, Dru\c{t}u and Sapir noted the existence of finitely generated non-linear residually finite groups based…

Group Theory · Mathematics 2023-09-26 Donsung Lee

We give a new proof that there are arbitrarily large indecomposable abelian groups; moreover, the groups constructed are absolutely indecomposable, that is, they remain indecomposable in any generic extension. However, any absolutely rigid…

Logic · Mathematics 2007-05-23 Paul C. Eklof , Saharon Shelah

We describe elementary examples of finitely presented sofic groups which are not residually amenable (and thus not initially subamenable or LEA, for short). We ask if an amalgam of two amenable groups over a finite subgroup is residually…

Group Theory · Mathematics 2015-09-03 Aditi Kar , Nikolay Nikolov

We study systematically groups whose marked finite quotients form a recursive set. We give several definitions, and prove basic properties of this class of groups, and in particular emphasize the link between the growth of the depth…

Group Theory · Mathematics 2021-10-27 Emmanuel Rauzy

We introduce a new class of Abelian groups which lies strictly between the classes of co-Hopfian groups and Dedekind-finite groups, calling these groups {\it Bassian-finite}. We prove the surprising fact that in the torsion case the…

Group Theory · Mathematics 2025-07-16 Peter V. Danchev , Patrick W. Keef

We investigate structural properties of non-sofic groups, assuming that such groups exist. We introduce and study two classes: minimal non-sofic groups and $\omega$-non-sofic groups. For minimal non-sofic groups, we establish strong…

Group Theory · Mathematics 2026-05-18 Kıvanç Ersoy

We study a family of finitely generated residually finite groups. These groups are doubles $F_2*_H F_2$ of a rank-$2$ free group $F_2$ along an infinitely generated subgroup $H$. Varying $H$ yields uncountably many groups up to isomorphism.

Group Theory · Mathematics 2022-07-11 Hip Kuen Chong , Daniel T. Wise

We introduce two families of two-generator one-relator groups called primitive extension groups and show that a one-relator group is hyperbolic if its primitive extension subgroups are hyperbolic. This reduces the problem of characterising…

Group Theory · Mathematics 2026-01-28 Marco Linton

We prove that with probability tending to 1, a 1-relator group with at least 3 generators and relator of length n is residually finite, virtually residually (finite p)-group for all sufficiently large p, and coherent. The proof uses both…

Group Theory · Mathematics 2009-09-13 Mark Sapir , Iva Spakulova

We give an example of a sofic group, which is not a limit of amenable groups.

Group Theory · Mathematics 2011-05-17 Yves Cornulier

We show that residually finite by residually finite extensions are weakly sofic.

Group Theory · Mathematics 2019-10-22 Lev Glebsky

We construct examples of non-bi-orderable one-relator groups without generalized torsion. This answers a question asked in [2].

Group Theory · Mathematics 2026-04-16 Azer Akhmedov , James Thorne
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