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Related papers: Note on the Cantor-Bendixson rank of limit groups

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We describe all finite subsemigroups of a free left regular band of infinite rank. Moreover, we show applications of this result in algebraic geometry and model theory.

Algebraic Geometry · Mathematics 2019-10-24 Artem N. Shevlyakov

Let $E$ be an elliptic curve over $\mathbb{Q}$ and $G=\langle\sigma_1, \dots, \sigma_n\rangle$ be a finitely generated subgroup of $\operatorname{Gal}(\overline{\mathbb{Q}}/ \mathbb{Q})$. Larsen's conjecture claims that the rank of the…

Number Theory · Mathematics 2024-11-22 A. Hadavand

We construct first examples of infinite finitely generated residually finite torsion groups with positive rank gradient. In particular, these groups are non-amenable. Some applications to problems about cost and $L^2$-Betti numbers are…

Group Theory · Mathematics 2014-02-26 D. Osin

We prove that a self-similar free abelian group has finite rank. We apply the result to self-similar wreath products of abelian groups $G=BwrX$. We show that if $X$ is torsion-free, then $B$ is torsion of finite exponent. Furthemore, we…

Group Theory · Mathematics 2017-01-31 Alex C. Dantas , Said N. Sidki

In this article, we classify disconnected reductive groups over an algebraically closed field with a few caveats. Internal parts of our result are both a classification of finite groups and a classification of integral representations of a…

Representation Theory · Mathematics 2024-09-20 Dylan Johnston , Diego Martín Duro , Dmitriy Rumynin

Let FL_s(K) be the finitary linear group of degree s over an associative ring K with unity. We prove that the torsion subgroups of FL_s(K) are locally finite for certain classes of rings K. A description of some f.g. solvable subgroups of…

Group Theory · Mathematics 2020-04-28 V. A. Bovdi , O. Yu. Dashkova , M. A. Salim

We prove that a limit group over Thompson's group $F$ cannot be an HNN-extension of $F$ with respect to a finitely generated subgroup. On the other hand we give an example of an $F$-limit group which is a centralized HNN-extenstions of $F$.…

Group Theory · Mathematics 2025-09-25 Aleksander Ivanov , Roland Zarzycki

We formulate and analyze several finiteness conjectures for linear algebraic groups over higher-dimensional fields. In fact, we prove all of these conjectures for algebraic tori as well as in some other situations. This work relies in an…

Number Theory · Mathematics 2020-02-18 Andrei S. Rapinchuk , Igor A. Rapinchuk

By imposing conditions upon the index of a self-centralizing subgroup of a group, and upon the index of the center of the group, we are able to classify the Chermak-Delgado lattice of the group. This is our main result. We use this result…

Group Theory · Mathematics 2025-03-18 Ryan McCulloch , Marius Tărnăuceanu

The Hadamard rank of a point with respect to a projective variety is, if it exists, the minimum number of points of the variety whose coordinate-wise product is the given point. We classify the projective varieties for which the Hadamard…

Algebraic Geometry · Mathematics 2026-04-01 Dario Antolini , Edoardo Ballico , Alessandro Oneto

We consider limits over categories of extensions and show how certain well-known functors on the category of groups turn out as such limits. We also discuss higher (or derived) limits over categories of extensions.

Category Theory · Mathematics 2009-05-21 Roman Mikhailov , Inder Bir S. Passi

We classify all finite groups with five relative commutativity degrees. Also, we give a partial answer to our previous conjecture on a lower bound of the number of relative commutativity degrees of finite groups.

Group Theory · Mathematics 2019-12-11 Mohammad Farrokhi Derakhshandeh Ghouchan

We establish conditions under which the fundamental group of a graph of finite $p$-groups is necessarily residually $p$-finite. The technique of proof is independent of previously established results of this type, and the result is also…

Group Theory · Mathematics 2018-11-01 Gareth Wilkes

We consider dense 2-generator multiplicative subgroups in $\mathbb C$ and show that for each point $z\in \mathbb C$ the set of limit values for the arguments of the powers of each generator at the point $z$ is either finite or is…

Dynamical Systems · Mathematics 2014-10-23 Kirill Kamalutdinov , Andrey Tetenov , Dmitry Vaulin

We determine the finite groups whose real irreducible representations have different degrees.

Group Theory · Mathematics 2025-05-08 Thomas Breuer , Frank Calegari , Silvio Dolfi , Gabriel Navarro , Pham Huu Tiep

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

We describe an error in the proof of a key proposition, which was necessary for the proof of the main result. Alternate proofs of the main result are given by Ozsvath-Stipsicz-Szabo and Dai-Hom-Stoffregen-Truong.

Geometric Topology · Mathematics 2019-10-23 Jennifer Hom

We determine the lower rank of the direct product of finitely many hereditarily just infinite profinite groups of finite lower rank.

Group Theory · Mathematics 2018-01-16 Benjamin Klopsch , Matteo Vannacci

Let $\lambda(G)$ be the maximum number of subgroups in an irredundant covering of a finite group $G$. We prove that the finite groups with $\lambda(G)=|G|-t$, where $t\leq 5$, are solvable, and classify such groups.

Group Theory · Mathematics 2021-03-22 Lifang Wang , Lijian An

Residual finiteness growth gives an invariant that indicates how well-approximated a finitely generated group is by its finite quotients. We briefly survey the state of the subject. We then improve on the best known upper and lower bounds…

Group Theory · Mathematics 2019-09-17 Khalid Bou-Rabee , Junjie Chen , Anastasiia Timashova