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Given a variety of universal algebras. A method is suggested for describing automorphisms of a category of free algebras of this variety. Applying this general method all automorphisms of such categories are found in two cases: 1) for the…

Rings and Algebras · Mathematics 2007-05-23 Boris Plotkin , Grigori Zhitomirski

We investigate the relationship between finite groups and incidence geometries through their automorphism structures. Building upon classical results on the realizability of groups as automorphism groups of graphs, we develop a general…

Group Theory · Mathematics 2025-12-17 Antonio Díaz Ramos , Rémi Molinier , Antonio Viruel

Let $A_n$ be an $n$-dimensional algebra with zero multiplication over a field $K$ of characteristic $0$. Then its universal (multiplicative) enveloping algebra $U_n$ in the variety of left-symmetric algebras is a homogeneous quadratic…

Rings and Algebras · Mathematics 2025-07-01 D. Zhangazinova , A. Naurazbekova , U. Umirbaev

Let $\Gamma_{g,b}$ denote the orientation-preserving Mapping Class Group of a closed orientable surface of genus $g$ with $b$ punctures. For a group $G$ let $\Phi_f(G)$ denote the intersection of all maximal subgroups of finite index in…

Geometric Topology · Mathematics 2015-02-05 G. Masbaum , A. W. Reid

Suppose that R is an ordered ring, G_n(R) is a subsemigroup of $GL_n(R)$, consisting of all matrices with nonnegative elements. A.V. Mikhalev and M.A. Shatalova described all automorphisms of G_n(R), where R is a linearly ordered skewfield…

Rings and Algebras · Mathematics 2007-11-06 E. I. Bunina , P. P. Semenov

For $n \in \mathbb{N}$, let $[n] = \{1, 2, \ldots, n\}$ be an $n$ - element set. As usual, we denote by $I_n$ the symmetric inverse semigroup on $[n]$, i.e. the partial one-to-one transformation semigroup on $[n]$ under composition of…

Rings and Algebras · Mathematics 2023-10-18 Ilinka Dimitrova , Jörg Koppitz

Let p be an odd prime, F the field of p elements and G a finite abelian p-group with an arbitrary involutory automorphism. Extend this automorphism to the group algebra FG and consider the unitary and the symmetric normalized units of FG.…

Group Theory · Mathematics 2007-05-23 A. Bovdi , A. Szakacs

In this paper we compute the automorphism groups $\operatorname{Aut}(\mathbf{P}_n(\Sigma))$ and $\operatorname{Aut}(\mathbf{B}_n(\Sigma))$ of braid groups $\mathbf{P}_n(\Sigma)$ and $\mathbf{B}_n(\Sigma)$ on every orientable surface…

Geometric Topology · Mathematics 2021-01-11 Byung Hee An

Here we study some algebraic properties of non-cyclic graphs. In this paper we show that $\overline{\Gamma}_G$ is isomorphic to $K_3\cup (n-4)K_1$ or $K_4\cup (n-5)K_1$ if and only if $G$ is isomorphic to $D_8$ or $D_{10}$, respectively. We…

Group Theory · Mathematics 2017-01-11 Ebrahim Vatandoost , Yasser Golkhandy Pour

We show the inverse deformation problem has an affirmative answer: given a complete local noetherian ring $A$ with finite residue field $\pmb{k}$, we show that there is a topologically finitely generated profinite group $\Gamma$ and an…

Rings and Algebras · Mathematics 2019-02-20 Timothy Eardley , Jayanta Manoharmayum

In this paper we will study the structure of algebras A(Gamma) associated to two directed, layered graphs Gamma. These are algebras associated with Hasse graphs of n-gons and the algebras Q_n related to pseudoroots of noncommutative…

Rings and Algebras · Mathematics 2008-05-01 Colleen Duffy

Let $G$ be a (finite or infinite) group, and let $K_G = \mathrm{Cay} ( G;G \smallsetminus \{1\} )$ be the complete graph with vertex set $G$, considered as a Cayley graph of $G$. Being a Cayley graph, it has a natural edge-colouring by sets…

Combinatorics · Mathematics 2024-04-16 Shirin Alimirzaei , Dave Witte Morris

This paper aims at generalizing some geometric properties of Grassmannians of finite dimensional vector spaces to the case of Grassmannnians of infinite dimensional ones, in particular for that of $k((z))$. It is shown that the Determinant…

Algebraic Geometry · Mathematics 2016-08-15 Francisco J. Plaza Martín

Toral automorphisms, represented by unimodular integer matrices, are investigated with respect to their symmetries and reversing symmetries. We characterize the symmetry groups of GL(n,Z) matrices with simple spectrum through their…

Dynamical Systems · Mathematics 2019-07-16 Michael Baake , John A. G. Roberts

Extending earlier work of Guralnick and of Cai and Zhang, we classify the almost simple groups which have transitive permutation representations of prime power degree $p^k$, and those which have $p$-complements (stabilisers of order coprime…

Group Theory · Mathematics 2024-03-19 Gareth A. Jones , Sezgin Sezer

This research was motivated by universal algebraic geometry. One of the central questions of universal algebraic geometry is: when two algebras have the same algebraic geometry? For answer of this question (see [Pl],[Ts]) we must consider…

Group Theory · Mathematics 2007-05-23 A. Tsurkov

We give a complete classification to when a finite group of outer automorphisms preserves a bi-order on a non-abelian free group and bi-orderable surface groups. We also give another new criterion for an outer automorphism of $F_n$ induced…

Group Theory · Mathematics 2026-04-24 Jonathan Johnson , Khanh Le

The aim of this paper is to use the framework of incidence geometry to develop a theory that permits to model both the inner and outer automorphisms of a group G simultaneously. More precisely, to any group G, we attempt to associate an…

Group Theory · Mathematics 2025-06-13 Dimitri Leemans , Klara Stokes , Philippe Tranchida

Let $\Lambda (f) = K[x][y; f\frac{d}{dx} ]$ be an Ore extension of a polynomial algebra $K[x]$ over an arbitrary field $K$ of characteristic $p>0$ where $f\in K[x]$. For each polynomial $f$, the automorphism group of the algebras $\Lambda…

Rings and Algebras · Mathematics 2021-07-22 V. V. Bavula

Let $G$ be a finitely generated malabelian group, let $A\leq\mathrm{Out}(G)$ be a finitely generated subgroup, and let $\Gamma_{G,A}$ denote the preimage of $A$ in $\mathrm{Aut}(G)$. We give a general criterion for the linearity of…

Group Theory · Mathematics 2025-10-17 Thomas Koberda , Mark Pengitore