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Let $G$ be a finite group and $cd(G)$ denote the set of complex irreducible character degrees of $G$. In this paper, we prove that if $G$ is a finite group and $H$ is an almost simple group whose socle is Mathieu group such that $cd(G)…

Group Theory · Mathematics 2016-01-26 Seyed Hassan Alavi , Ashraf Daneshkhah , Ali Jafari

We give a survey of recent results related to the problem of characterizing finite-dimensional division algebras by the set of isomorphism classes of their maximal subfields. We also discuss various generalizations of this problem and some…

Rings and Algebras · Mathematics 2015-06-11 Vladimir I. Chernousov , Andrei S. Rapinchuk , Igor A. Rapinchuk

In this paper we study categorical properties of the category of abelian hypergroups that leads to the notion of hyper (almost) preadditive and hyper (almost) abelian categories. Our goal is to create a path towards a general theory of…

Category Theory · Mathematics 2025-09-11 Kaique Matias de Andrade Roberto , Ana Luiza Tenório

We study the notion of fundamental group in the framework of descent-exact homological categories. This setting is sufficiently wide to include several categories of "algebraic" nature such as the almost abelian categories, the semi-abelian…

Category Theory · Mathematics 2016-04-13 Mathieu Duckerts-Antoine

We call an affine algebraic supergroup quasireductive if its underlying algebraic group is reductive. We obtain some results about the structure and representations of reductive supergroups.

Representation Theory · Mathematics 2023-10-19 Vera Serganova

We study actions of connected algebraic groups on normal algebraic varieties, and show how to reduce them to actions of affine subgroups.

Algebraic Geometry · Mathematics 2007-05-23 Michel Brion

The classification of gradings by abelian groups on finite direct sums of simple finite-dimensional nonassociative algebras over an algebraically closed field is reduced, by means of the use of loop algebras, to the corresponding problem…

Rings and Algebras · Mathematics 2019-04-25 Alejandra S. Córdova-Martínez , Alberto Elduque

A toroidal affine Nash group is the affine Nash group analogue of an anti-affine algebraic group. In this note, we prove analogues of Rosenlicht's structure and decomposition theorems: (1) Every affine Nash group $G$ has a smallest normal…

Algebraic Geometry · Mathematics 2016-04-08 Mahir Bilen Can

We develop the theory of difference algebraic groups in the case where we have finitely many pairwise commuting difference operators. We show that the defining ideal of a difference algebraic group is finitely generated as a difference…

Algebraic Geometry · Mathematics 2026-05-08 Orla McGrath

In this paper, the complete algebraic structure of finite semisimple group algebra of a normally monomial group is described. The main result is illustrated by computing the explicit Wedderburn decomposition of finite semisimple group…

Rings and Algebras · Mathematics 2017-07-27 Shalini Gupta , Sugandha Maheshwary

Let G be a finite group and cd(G) denote the set of complex irreducible character degrees of G. In this paper, we prove that if G is a finite group and H is an almost simple group whose socle is a sporadic simple group H0 such that cd(G) =…

Group Theory · Mathematics 2016-03-01 Seyed Hassan Alavi , Ashraf Daneshkhah , Ali Jafari

We show that for algebraic groups over local fields of characteristic zero, the following are equivalent: Every homomorphism has a closed image, every unitary representation decomposes into a direct sum of finite-dimensional and mixing…

Group Theory · Mathematics 2024-04-16 Elyasheev Leibtag

Let $R$ be a finite-dimensional algebra over an algebraically closed field $F$ graded by an arbitrary group $G$. We prove that $R$ is a graded division algebra if and only if it is isomorphic to a twisted group algebra of some finite…

Rings and Algebras · Mathematics 2007-05-23 Y. A. Bahturin , S. K. Sehgal , M. V. Zaicev

For a mixing shift of finite type, the associated automorphism group has a rich algebraic structure, and yet we have few criteria to distinguish when two such groups are isomorphic. We introduce a stabilization of the automorphism group,…

Dynamical Systems · Mathematics 2020-01-28 Yair Hartman , Bryna Kra , Scott Schmieding

In this short note we prove that any irreducible algebraic monoid whose unit group is an affine algebraic group is affine.

Algebraic Geometry · Mathematics 2007-05-23 Alvaro Rittatore

Albert algebras, a specific kind of Jordan algebra, are naturally distinguished objects among commutative non-associative algebras and also arise naturally in the context of simple affine group schemes of type $F_4$, $E_6$, or $E_7$. We…

Rings and Algebras · Mathematics 2023-03-15 Skip Garibaldi , Holger P. Petersson , Michel L. Racine

We study the inverse problem in the difference Galois theory of linear differential equations over the difference-differential field $\mathbb{C}(x)$ with derivation $\frac{d}{dx}$ and endomorphism $f(x)\mapsto f(x+1)$. Our main result is…

Algebraic Geometry · Mathematics 2020-03-25 Annette Bachmayr , Michael Wibmer

We introduce the spin Hecke algebra, which is a q-deformation of the spin symmetric group algebra, and its affine generalization. We establish an algebra isomorphism which relates our spin (affine) Hecke algebras to the (affine)…

Representation Theory · Mathematics 2011-11-09 Weiqiang Wang

For any finitely generated abelian group $Q$, we reduce the problem of classification of $Q$-graded simple Lie algebras over an algebraically closed field of "good" characteristic to the problem of classification of gradings on simple Lie…

Representation Theory · Mathematics 2016-11-29 Volodymyr Mazorchuk , Kaiming Zhao

In this paper we study abstract group homomorphisms between the groups of rational points of linear algebraic groups which are not necessarily reductive. One of our main goal is to obtain results on homomorphisms from the groups of rational…

Group Theory · Mathematics 2016-03-15 Pralay Chatterjee