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We give upper bounds on the order of the automorphism group of a simple graph

Combinatorics · Mathematics 2007-05-23 Ilia Krasikov , Arie Lev , Bhalchandra D. Thatte

Prolongations of a group extension can be studied in a more general situation that we call group extensions of the co-type of a crossed module. Cohomology classification of such extensions is obtained by applying the obstruction theory of…

Category Theory · Mathematics 2015-03-17 Nguyen Tien Quang

In this paper we construct two groupoids from morphisms of groupoids, with one from a categorical viewpoint and the other from a geometric viewpoint. We show that for each pair of groupoids, the two kinds of groupoids of morphisms are…

Category Theory · Mathematics 2019-08-16 Bohui Chen , Cheng-Yong Du , Rui Wang

A monomial algebra B is defined as a quotient of a polynomial ring by a monomial ideal, which is an ideal generated by a finite set of monomials. In this paper, we determine the automorphism group of a monomial algebra B, under the…

Algebraic Geometry · Mathematics 2026-04-28 Roberto Díaz , Alvaro Liendo , Gonzalo Manzano-Flores , Andriy Regeta

For a subshift over a finite alphabet, a measure of the complexity of the system is obtained by counting the number of nonempty cylinder sets of length $n$. When this complexity grows exponentially, the automorphism group has been shown to…

Dynamical Systems · Mathematics 2014-03-04 Van Cyr , Bryna Kra

We associate each endomorphism of a finite cyclic group with a digraph and study many properties of this digraph, including its adjacent matrix and automorphism group.

Combinatorics · Mathematics 2011-08-16 Min Sha

We describe the automorphism groups of reductive monoids and of root monoids with active groups of invertible elements.

Algebraic Geometry · Mathematics 2026-05-13 Anton Shafarevich

The inner automorphisms of a group G can be characterized within the category of groups without reference to group elements: they are precisely those automorphisms of G that can be extended, in a functorial manner, to all groups H given…

Rings and Algebras · Mathematics 2013-05-10 George M. Bergman

In this paper, we have computed the automorphism groups of all groups of order $p^{2}q^{2}$, where $p$ and $q$ are distinct primes.

Group Theory · Mathematics 2022-10-20 Ratan Lal , Vipul Kakkar

When G is a finite abelian group, we define G-spans of groupoids and their associated matrices with entries in the group ring QG and show that composition of spans corresponds to multiplication of matrices.

Category Theory · Mathematics 2026-03-24 Joachim Kock , Jesper M. Møller

An automorphism of a group is called outer if it is not an inner automorphism. Let $G$ be a finite $p$-group. Then for every outer $p$-automorphism $\phi$ of $G$ the subgroup $C_G(\phi)=\{x\in G \;|\; x^\phi=x\}$ has order $p$ if and only…

Group Theory · Mathematics 2013-07-23 Alireza Abdollahi , S. Mohsen Ghoraishi

We give some applications of augmentation quotients of free group rings in group theory.

Representation Theory · Mathematics 2012-02-01 Deepak Gumber

We study the automorphisms group action on a bounded domain in $\CC^n$ having a boundary point that is exponentially flat. Such a domain typically has a compact automorphism group. Our results enable us to generate many new examples.

Complex Variables · Mathematics 2010-10-08 Steven G. Krantz

The groups of automorphisms of the Lie algebras of unitriangular polynomial derivations are found.

Algebraic Geometry · Mathematics 2013-11-07 V. V. Bavula

We refine the construction of quasi-homomorphisms on mapping class groups. It is useful to know that there are unbounded quasi-homomorphisms which are bounded when restricted to particular subgroups since then one deduces that the mapping…

Group Theory · Mathematics 2007-05-23 Mladen Bestvina , Koji Fujiwara

This article initiates a geometric study of the automorphism groups of general graph products of groups, and investigates the algebraic and geometric structure of automorphism groups of cyclic product of groups. For a cyclic product of at…

Group Theory · Mathematics 2018-03-21 Anthony Genevois , Alexandre Martin

This article focuses on the study of cut groups, i.e., the groups which have only trivial central units in their integral group ring. We provide state of art for cut groups. The results are compiled in a systematic manner and have also been…

Rings and Algebras · Mathematics 2025-05-15 Seema Chahal , Sugandha Maheshwary

A description of group automorphisms of all two-dimensional algebras, considered up to isomorphism, over any basic field is provided.

Rings and Algebras · Mathematics 2024-11-19 Sh. Eshmirzayev , U. Bekbaev

A group, defined as set with associative multiplication and inverse, is a natural structure describing the symmetry of a space. The concept of group generalizes to group objects internal to other categories than sets. But there are yet more…

Symplectic Geometry · Mathematics 2007-05-23 Christian Blohmann , Alan Weinstein

The description of the automorphism group of group $<a, b; [a^m,b^n]=1>$ ($m,n>1$) in terms of generators and defining relations is given. This result is applied to prove that any normal automorphism of every such group is inner.

Group Theory · Mathematics 2007-05-23 D. Tieudjo , D. I. Moldavanskii