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We prove that a variety of algebras whose finitely generated members are free must be definitionally equivalent to the variety of sets, the variety of pointed sets, a variety of vector spaces over a division ring, or a variety of affine…

Rings and Algebras · Mathematics 2016-09-13 Keith A. Kearnes , Emil W. Kiss , Agnes Szendrei

Infinite products, indexed by countably infinite linear orders, arise naturally in the context of fundamental groupoids. Such products are called "transfinite" if the index orders are permitted to contain a dense suborder and are called…

Algebraic Topology · Mathematics 2025-01-27 Jeremy Brazas

We prove the finite generation of canonical rings of projective variety of general type defined over complex numbers.

Algebraic Geometry · Mathematics 2007-05-23 Hajime Tsuji

Let $\mathcal{C}$ be a class of finite groups closed for subgroups, quotients groups and extensions. Let $\Gamma$ be a finite simplicial graph and $G = G_{\Gamma}$ be the corresponding pro-$\mathcal C$ RAAG. We show that if $N$ is a…

Group Theory · Mathematics 2023-05-08 Dessislava Kochloukova , Pavel Zalesskii

We prove that every finite direct product of crystallographic groups arising from an irreducible root system (in the sense of Lie theory) is profinitely rigid (equiv. first-order rigid). This is a generalization of recent proofs of…

Group Theory · Mathematics 2025-06-19 Davide Carolillo , Gianluca Paolini

We consider the finite generation property for cohomology algebra of pointed finite tensor categories via de-equivariantization and exact sequence of finite tensor categories. As a result, we prove that all coradically graded pointed finite…

Quantum Algebra · Mathematics 2026-02-10 Bowen Li , Gongxiang Liu

We give an example of a finitely presented simple group containing a finitely generated subgroup which is not finitely presented.

Group Theory · Mathematics 2007-05-23 Diego Rattaggi

We prove that the crossed product AxG of a unital finitely generated MF algebra A by a discrete finitely generated amenable residually finite group G is an MF algebra, provided that the action is almost periodic. This generalizes a result…

Operator Algebras · Mathematics 2017-05-29 Weihua Li , Stefanos Orfanos

Among all affine, flat, finitely presented group schemes, we focus on those that are pure, this includes all groups which are extensions of a finite locally free group by a group with connected fibres. We prove that over an arbitrary base…

Algebraic Geometry · Mathematics 2018-08-08 Giulia Battiston , Matthieu Romagny

We show that if a group can be represented as a graph product of finite directly indecomposable groups, then this representation is unique.

Group Theory · Mathematics 2010-08-09 David G. Radcliffe

Let $\mathcal G$ denote the space of finitely generated marked groups. For any finitely generated group $G$, we construct a continuous, injective map $f$ from the space of subgroups $Sub(G)$ to $\mathcal G$ that sends conjugate subgroups to…

Group Theory · Mathematics 2024-03-27 D. Osin

Using quantum representations of mapping class groups we prove that profinite completions of Burnside-type surface group quotients are not virtually prosolvable, in general. Further, we construct infinitely many finite simple characteristic…

Geometric Topology · Mathematics 2019-01-25 Louis Funar , Pierre Lochak

We define and study the class of positively finitely related (PFR) profinite groups. Positive finite relatedness is a probabilistic property of profinite groups which provides a first step to defining higher finiteness properties of…

Group Theory · Mathematics 2020-03-25 Steffen Kionke , Matteo Vannacci

We settle an old conjecture of Karrass and Solitar by proving that a finitely generated subgroup of a non-trivial free product $G = A\ast B$ has finite index if and only if it intersects non-trivially each non-trivial normal subgroup of…

Group Theory · Mathematics 2013-11-08 Benjamin Steinberg

We show that up to commensurability there are only finitely many cocompact arithmetic Kleinian groups generated by rotations. This implies, in particular, that there exist only finitely many conjugacy classes of cocompact two generated…

Geometric Topology · Mathematics 2017-07-11 Mikhail Belolipetsky

We show that finite (i.e. locally finite and decomposition-finite) objects of a connected Grothendieck topos span a Boolean pretopos with an essentially unique Galois point. The automorphism group of this point carries a profinite topology…

Category Theory · Mathematics 2025-05-06 Clemens Berger , Victor Iwaniack

We prove that every finitely generated, residually finite group $G$ embeds into a finitely generated perfect branch group $\Gamma$ such that many properties of $G$ are preserved under this embedding. Among those are the properties of being…

Group Theory · Mathematics 2024-03-06 Steffen Kionke , Eduard Schesler

We obtain a complete classification of graph products of finite abelian groups whose Cayley graphs with respect to the standard presentations are planar.

Group Theory · Mathematics 2019-02-28 Olga Varghese

A finitely generated solvable group with unbounded iterated identity is constructed.

Group Theory · Mathematics 2018-08-03 Roman Mikhailov

This paper establishes strong profinite rigidity results for K\"ahler groups, showing that certain groups are determined within the class of residually finite K\"ahler groups by their profinite completion. Examples include products of…

Geometric Topology · Mathematics 2025-01-24 Sam Hughes , Claudio Llosa Isenrich , Pierre Py , Matthew Stover , Stefano Vidussi