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A group $G$ has cube-free order if no prime to the third power divides $|G|$. We describe an algorithm that given two cube-free groups $G$ and $H$ of known order, decides whether $G\cong H$, and, if so, constructs an isomorphism $G\to H$.…

Group Theory · Mathematics 2019-05-06 Heiko Dietrich , James B. Wilson

The question whether non-isomorphic finite $p$-groups can have isomorphic modular group algebras was recently answered in the negative by Garc\'ia-Lucas, Margolis and del R\'io [J. Reine Angew. Math. 783 (2022), pp. 269-274]. We embed these…

Rings and Algebras · Mathematics 2025-08-14 Leo Margolis , Taro Sakurai

We describe those group algebras over fields of characteristic different from 2 whose units symmetric with respect to the classical involution, satisfy some group identity.

Rings and Algebras · Mathematics 2007-05-23 Victor Bovdi

We show that the modular isomorphism problem has a positive answer for groups of nilpotency class 2 with cyclic center, i.e. that for such p-groups G and H an isomorphism between the group algebras FG and FH implies an isomorphism of the…

Group Theory · Mathematics 2023-06-13 Diego García-Lucas , Leo Margolis

Let $p$ be a an odd prime and let $G$ be a finite $p$-group with cyclic commutator subgroup $G'$. We prove that the exponent and the abelianization of the centralizer of $G'$ in $G$ are determined by the group algebra of $G$ over any field…

Group Theory · Mathematics 2022-09-23 Diego García-Lucas , Ángel del Río , Mima Stanojkovski

We consider the group isomorphism problem: given two finite groups G and H specified by their multiplication tables, decide if G and H are isomorphic. The n^(log n) barrier for group isomorphism has withstood all attacks --- even for the…

Data Structures and Algorithms · Computer Science 2013-12-12 David Rosenbaum

Let $FG$ be the group algebra of a finite $p$-group $G$ over a finite field $F$ of positive characteristic $p$. Let $\cd$ be an involution of the algebra $FG$ which is a linear extension of an anti-automorphism of the group $G$ to $FG$. If…

Group Theory · Mathematics 2022-06-07 Zsolt Adam Balogh

Let F be the field of two elements and G a finite abelian 2-group with an involutory automorphism. The extension of this automorphism to the group algebra FG is called an involutory involution. This determines the groups of unitary and…

Rings and Algebras · Mathematics 2019-07-10 V. A. Bovdi , A. N. Grishkov

We study the Modular Isomorphism Problem (MIP) for groups of small order based on an improvement of an algorithm described by B. Eick. Our improvement allows to determine quotients $I(kG)/I(kG)^m$ of the augmentation ideal without first…

Group Theory · Mathematics 2021-07-07 L. Margolis , T. Moede

We give a complete classification (up to isomorphism) of Lie conformal algebras which are free of rank two as $\C[\partial]$-modules, and determine their automorphism groups.

Representation Theory · Mathematics 2019-07-12 Rekha Biswal , Abdelkarim Chakhar , Xiao He

This paper studies the loop algebras that arise from pairs consisting of a symmetrizable Kac-Moody Lie algebra $\g$ and a finite order automorphism $\sigma$ of $\g$. We obtain necessary and sufficient conditions for two such loop algebras…

Quantum Algebra · Mathematics 2007-05-23 Bruce Allison , Stephen Berman , Arturo Pianzola

The Subgroup Isomorphism Problem for Integral Group Rings asks for which finite groups U it is true that if U is isomorphic to a subgroup of V(ZG), the group of normalized units of the integral group ring of the finite group G, it must be…

Rings and Algebras · Mathematics 2016-06-01 Leo Margolis

We study the Modular Isomorphism Problem applying a combination of existing and new techniques. We make use of the small group algebra to give a positive answer for two classes of groups of nilpotency class 3. We also introduce a new…

Rings and Algebras · Mathematics 2023-09-25 L. Margolis , M. Stanojkovski

The isomorphism problem means to decide if two given finite-dimensional simple algebras over the same centre are isomorphic and, if so, to construct an isomorphism between them. A solution to this problem has applications in computational…

Rings and Algebras · Mathematics 2007-05-23 Timo Hanke

We obtain a new classification of the finite metacyclic group in terms of group invariants. We present an algorithm to compute these invariants, and hence to decide if two given finite metacyclic groups are isomorphic, and another algorithm…

Group Theory · Mathematics 2023-03-02 Àngel García-Blázquez , Ángel del Río

As a result of impressive research arXiv:2106.07231, D. Garc\'{\i}a-Lucas, \'{A}. del R\'{i}o and L. Margolis defined an infinite series of non-isomorphic $2$-groups $G$ and $H$, whose group algebras $\mathbb{F}G$ and $\mathbb{F}H$ over the…

Group Theory · Mathematics 2024-08-13 Czesław Bagiński , Kamil Zabielski

Let $p$ be a prime and let $G$ be a finite $p$-group. We show that the isomorphism type of the maximal abelian direct factor of $G$, as well as the isomorphism type of the group algebra over $\mathbb F_p$ of the non-abelian remaining direct…

Group Theory · Mathematics 2022-11-16 Diego García-Lucas

In this paper we define a pair of faithful functors that map isomorphic and isotopic finite-dimensional algebras over finite fields to isomorphic graphs. These functors reduce the cost of computation that is usually required to determine…

Rings and Algebras · Mathematics 2017-02-08 O. J. Falcón , R. M. Falcón , J. Núñez , A. M. Pacheco , M. T. Villar

We consider 9 infinite families of finite $p$-groups, for $p$ a prime, and we settle the isomorphism problem that arises when the parameters that define these groups are modified.

Group Theory · Mathematics 2024-02-07 Alexander Montoya Ocampo , Fernando Szechtman

Necessary and sufficient conditions are given for a $G$-graded simple module over a unital associative algebra, graded by an abelian group $G$, to be isomorphic to a loop module of a simple module, as well as for two such loop modules to be…

Representation Theory · Mathematics 2016-09-12 Alberto Elduque , Mikhail Kochetov