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Given a finite group $G$, we denote by $L(G)$ the subgroup lattice of $G$ and by ${\rm Isolated}(G)$ the set of isolated subgroups of $G$. In this note, we describe finite groups $G$ such that $|{\rm Isolated}(G)|=|L(G)|-k$, where…

Group Theory · Mathematics 2021-11-30 Marius Tărnăuceanu

Let $\mathfrak{Nil}$ be the class of nilpotent groups. This article explores the finiteness of meta and para-$\mathfrak{Nil}$-Hamiltonian groups or their derived subgroups when these groups contain a soluble subgroup of finite index or a…

Group Theory · Mathematics 2025-02-11 Hamid Mousavi

Let $\mathfrak{Nil}$ be the class of nilpotent groups and $G$ be a group. We call $G$ a meta-$\mathfrak{Nil}$-Hamiltonian group if any of its non-$\mathfrak{Nil}$ subgroups is normal. Also, we call $G$ a para-$\mathfrak{Nil}$-Hamiltonian…

Group Theory · Mathematics 2024-02-21 Nasrin Dastborhan , Hamid Mousavi

This is an introduction to the class of groups that are locally embeddable into finite groups.

Group Theory · Mathematics 2020-04-17 Melvyn B. Nathanson

In this paper we use families of finite subgroups to study Grothendieck rings associated to certain discrete groups, such as the arithmetic ones.

Group Theory · Mathematics 2016-09-06 Alejandro Adem

Let $G$ be a finite group and $A$ be a normal subgroup of $G$. We denote by $ncc(A)$ the number of $G$-conjugacy classes of $A$ and $A$ is called $n$-decomposable, if $ncc(A)=n$. Set ${\cal K}_G = \{ncc(A)| A \lhd G \}$. Let $X$ be a…

Group Theory · Mathematics 2007-08-07 Ali Reza Ashrafi , Geetha Venkataraman

The generalised Fitting subgroup of a finite group is the group generated by all subnormal subgroups that are either nilpotent or quasisimple. The importance of this subgroup in finite group theory stems from the fact that it always…

Group Theory · Mathematics 2009-04-03 Colin Reid

We consider the following two finiteness conditions on normalizers and centralizers in a group G: (i) |N_G(H):H| is finite for every non-normal subgroup H of G, and (ii) |C_G(x):<x>| is finite for every non-normal cyclic subgroup <x> of G.…

Group Theory · Mathematics 2016-01-14 Gustavo A. Fernandez-Alcober , Leire Legarreta , Antonio Tortora , Maria Tota

A Schmidt group is a non-nilpotent group whose every proper subgroup is nilpotent. We study the properties of a non-nilpotent group G in which every Schmidt subgroup is a Hall subgroup of G.

Group Theory · Mathematics 2011-04-07 V. N. Kniahina , V. S. Monakhov

The finite groups having an indecomposable polynomial invariant whose degree is at least half of the order of the group are classified. Apart from four sporadic exceptions these are exactly the groups having a cyclic subgroup of index at…

Representation Theory · Mathematics 2013-12-31 K. Cziszter , M. Domokos

A self-similar group of finite type is the profinite group of all automorphisms of a regular rooted tree that locally around every vertex act as elements of a given finite group of allowed actions. We provide criteria for determining when a…

Group Theory · Mathematics 2014-09-02 Ievgen V. Bondarenko , Igor O. Samoilovych

We will explore the nature of when certain finite groups have an equal covering, and when finite groups do not. Not to be confused with the concept of a cover group, a covering of a group is a collection of proper subgroups whose…

Group Theory · Mathematics 2022-07-01 Andrew Velasquez-Berroteran

We consider a finiteness condition on centralizers in a group G, namely that |C_G (x) : <x>| is finite for every non-normal cyclic subgroup <x> of G. For periodic groups, this is the same as |C_G (x)| is finite for every non-normal cyclic…

Group Theory · Mathematics 2015-10-14 Gustavo A. Fernandez-Alcober , Leire Legarreta , Antonio Tortora , Maria Tota

For any finite group Q not of prime power order, we construct a group G that is virtually of type F, contains infinitely many conjugacy classes of subgroups isomorphic to Q, and contains only finitely many conjugacy classes of other finite…

Group Theory · Mathematics 2014-11-11 Ian J Leary

The aim of this work is to offer a family of invariants that allows us to classify finite potent endomorphisms on arbitrary vector spaces, generalizing the classification of endomorphisms on finite-dimensional vector spaces. As a particular…

Rings and Algebras · Mathematics 2020-07-07 Fernando Pablos Romo

In this article we classify all $L_9$-free finite groups.

Group Theory · Mathematics 2023-06-30 Imke Toborg , Rebecca Waldecker , Clemens B. Tietze

A finite presentation < X | R > of a finite group is called `just finite' if removing any relation from R results in a presentation for an infinite group. It has been an open question (Kourovka Notebook, Problem 21.10) whether every finite…

Group Theory · Mathematics 2026-05-12 Marc Lackenby

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

Broadly speaking, a finiteness property of groups is any generalisation of the property of having finite order. A large part of infinite group theory is concerned with finiteness properties and the relationships between them. Profinite…

Group Theory · Mathematics 2010-02-16 Colin Reid

It is known that any locally graded group with finitely many derived subgroups of non-normal subgroups is finite-by-abelian. This result is generalized here, by proving that in a locally graded group $G$ the subgroup $\gamma_{k}(G)$ is…

Group Theory · Mathematics 2021-03-18 Fausto De Mari