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We describe gradings by finite abelian groups on the associative algebras of infinite matrices with finitely many nonzero entries, over an algebraically closed field of characteristic zero.

Rings and Algebras · Mathematics 2009-06-26 Yuri Bahturin , Mikhail Zaicev

Let $k$ be a field that is finitely generated over the field of rational numbers and $Br(k)$ the Brauer group of $k$. Let $X$ be an absolutely irreducible smooth projective variety over $k$, let $Br(X)$ be the cohomological…

Number Theory · Mathematics 2007-11-05 Alexei Skorobogatov , Yuri Zarhin

Let X be a smooth projective rational variety carrying a regular action of a finite abelian group G. We give examples of effective computation of the Brauer group of the quotient stack [X/G] in dimensions 2 and 3 using residues in Galois…

Algebraic Geometry · Mathematics 2024-10-08 Alena Pirutka , Zhijia Zhang

We give an analog of Frobenius' theorem about the factorization of the group determinant on the group algebra of finite abelian groups and we extend it into dihedral groups and generalized quaternion groups. Furthermore, we describe the…

Representation Theory · Mathematics 2014-05-09 N. Yamaguchi

We introduce group graded basic Morita equivalences between algebras deter- mined by blocks of normal subgroups, and by using the extended Brauer quotient, we show that they induce graded basic Morita equivalences at local levels.

Representation Theory · Mathematics 2017-05-04 Tiberiu Coconet , Andrei Marcus

The current paper is dedicated to the study of the classical $K_1$ groups of graded rings. Let $A$ be a $\Gamma$ graded ring with identity $1$, where the grading $\Gamma$ is an abelian group. We associate a category with suspension to the…

K-Theory and Homology · Mathematics 2014-04-11 Zuhong Zhang

We give a full classification, up to equivalence, of finite-dimensional graded division algebras over the field of real numbers. The grading group is any abelian group.

Rings and Algebras · Mathematics 2018-03-06 Yuri Bahturin , Mikhail Zaicev

In this article we calculate two aspects of the representation theory of a Brauer configuration algebra: its Cartan matrix, and the module length of its associated indecomposable projective modules. Then we introduce the concept of…

Representation Theory · Mathematics 2022-08-01 Alex Sierra Cárdenas

Let $k$ be a field containing an algebraically closed field of characteristic zero. If $G$ is a finite group and $D$ is a division algebra over $k$, finite dimensional over its center, we can associate to a faithful $G$-grading on $D$ a…

Rings and Algebras · Mathematics 2020-09-08 Eli Aljadeff , Darrell Haile , Yakov Karasik

We determine the blocks of the walled Brauer algebra in characteristic zero. These can be described in terms of orbits of the action of a Weyl group of type $A$ on a certain set of weights. In positive characteristic we give a linkage…

Representation Theory · Mathematics 2007-09-07 Anton Cox , Maud De Visscher , Stephen Doty , Paul Martin

Brauer Theory for a finite group can be viewed as a method for comparing the representations of the group in characteristic 0 with those in prime characteristic. Here we generalize much of the machinery of Brauer theory to the setting of…

Representation Theory · Mathematics 2013-01-24 John MacQuarrie , Peter Symonds

We classify, up to isomorphism, all gradings by an arbitrary abelian group on simple finitary Lie algebras of linear transformations (special linear, orthogonal and symplectic) on infinite-dimensional vector spaces over an algebraically…

Rings and Algebras · Mathematics 2012-12-04 Yuri Bahturin , Matej Brešar , Mikhail Kochetov

We study the Brauer groups of affine surfaces that are complements of singular hyperplane sections of smooth cubic surfaces over a field $k$ of characteristic $0$. We determine the Brauer group over the algebraic closure as a Galois module…

Algebraic Geometry · Mathematics 2025-10-30 Abdulmuhsin Alfaraj

We compute the $RO(A)$-graded coefficients of $A$-equivariant complex and real topological $K$-theory for $A$ a finite elementary abelian $2$-group, together with all products, transfers, restrictions, power operations, and Adams…

Algebraic Topology · Mathematics 2022-10-12 William Balderrama

In this paper we consider the Brauer groups of algebraic stacks and GIT quotients: the only algebraic stacks we consider in this paper are quotient stacks [X/G], where X is a smooth scheme of finite type over a field k, and G is a linear…

Algebraic Geometry · Mathematics 2021-06-29 Jaya Iyer , Roy Joshua

The Tate conjecture for divisors on varieties over number fields is equivalent to finiteness of $\ell$-primary torsion in the Brauer group. We show that this finiteness is actually uniform in one-dimensional families for varieties that…

Algebraic Geometry · Mathematics 2018-01-24 Anna Cadoret , François Charles

This note begins by observing that a graded central simple algebra, graded by an abelian group, is a graded Azumaya algebra and it is free over its centre. For a graded Azumaya algebra A free over its centre $R$, we show that K_i^{\gr} (A)…

K-Theory and Homology · Mathematics 2010-11-08 R. Hazrat , J. Millar

We attach to any commutative ring R a subgroup of the Brauer group of R, called the Brauer-Galois group of R. Its elements are the classes of the Azumaya R-algebras which can be represented, via Brauer equivalence, by a Galois extension of…

Rings and Algebras · Mathematics 2007-05-23 Philippe Nuss

In this short note we observe that the recent examples of derived-equivalent Calabi-Yau 3-folds with different fundamental groups also have different Brauer groups, using a little topological K-theory.

Algebraic Geometry · Mathematics 2018-06-18 Nicolas Addington

We describe (braided-)commutative algebras with non-degenerate multiplicative form in certain braided monoidal categories, corresponding to abelian metric Lie algebras (so-called Drinfeld categories). We also describe local modules over…

Category Theory · Mathematics 2010-05-26 Alexei Davydov , Vyacheslav Futorny