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Let $H$ be a semisimple Hopf algebra over an algebraically closed field $\mathbbm{k}$ of characteristic $p>\dim_{\mathbbm{k}}(H)^{1/2}$. We show that the antipode $S$ of $H$ satisfies the equality $S^2(h)=\mathbf{u}h\mathbf{u}^{-1}$, where…

Representation Theory · Mathematics 2022-01-31 Zhihua Wang , Gongxiang Liu , Libin Li

In this paper, we study some variations of the well-known It\^{o}-Michler theorem for $p$-Brauer characters using various inequalities involving the $p$-Brauer character degrees of finite groups. Several new criteria for the existence of a…

Group Theory · Mathematics 2018-03-15 Hung P. Tong-Viet

We determine the smallest irreducible Brauer characters for finite quasi-simple orthogonal type groups in non-defining characteristic. Under some restrictions on the characteristic we also prove a gap result showing that the next larger…

Representation Theory · Mathematics 2023-06-22 Kay Magaard , Gunter Malle

We study the notion of essential dimension for a linear representation of a finite group. In characteristic zero we relate it to the canonical dimension of certain products of Weil transfers of generalized Severi-Brauer varieties. We then…

Representation Theory · Mathematics 2014-06-19 Nikita A. Karpenko , Zinovy Reichstein

We compute the Brauer group of the moduli stack of elliptic curves over the integers, localizations of the integers, finite fields of odd characteristic, and algebraically closed fields of characteristic not $2$. The methods involved…

Algebraic Geometry · Mathematics 2020-10-21 Benjamin Antieau , Lennart Meier

We prove that the Brauer group of TMF is isomorphic to the Brauer group of the derived moduli stack of elliptic curves. Then, we compute the local Brauer group, i.e., the subgroup of the Brauer group of elements trivialized by some \'etale…

Algebraic Geometry · Mathematics 2023-01-30 Benjamin Antieau , Lennart Meier , Vesna Stojanoska

In this short note we show that representation and character varieties of discrete groups can be viewed as tensor products of suitable functors over the PROP of cocommutative Hopf algebras. Such view point has several interesting…

Rings and Algebras · Mathematics 2016-10-11 Martin Kassabov , Sasha Patotski

We prove a broad generalization of a theorem of W. Burnside on real characters using permutation characters. Under a necessary hypothesis, We can give some control on multiplicities (a result that needs the Classification of Finite Simple…

Group Theory · Mathematics 2021-01-08 Robert Guralnick , Gabriel Navarro

We describe two methods for computing $p$-modular Brauer character tables for groups of Lie type $G(p^f)$ in defining characteristic $p$, assuming that the ordinary character table of $G(p^f)$ is known, and the weight multiplicities of the…

Representation Theory · Mathematics 2018-09-21 Frank Lübeck

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

We introduce the relative units-Picard complex of an arbitrary morphism of schemes and apply it to the problem of describing the (cohomological) Brauer group of a (fiber) product of schemes in terms of the Brauer groups of the factors.…

Algebraic Geometry · Mathematics 2017-05-15 Cristian D. Gonzalez-Aviles

We prove that the quotient of the Brauer group of a product of varieties over k by the sum of the images of the Brauer groups of factors has finite exponent. The bulk of the proof concerns p-primary torsion in characteristic p. Our approach…

Algebraic Geometry · Mathematics 2025-10-03 Alexei N. Skorobogatov

We compute the irreducible constitutents of the product of the Weil character and the Steinberg character in those finite classical groups for which a Weil character is defined, namely the symplectic, unitary and general linear groups. It…

Representation Theory · Mathematics 2008-06-17 G. Hiss , A. Zalesski

Let $A$ be the locally unital algebra associated to a cyclotomic oriented Brauer category over an arbitrary algebraically closed field $\Bbbk$ of characteristic $p\ge 0$. The category of locally finite dimensional representations of $A $ is…

Representation Theory · Mathematics 2021-07-06 Mengmeng Gao , Hebing Rui , Linliang Song

Ng and Schauenburg generalized higher Frobenius-Schur indicators to pivotal fusion categories and showed that these indicators may be computed utilizing the modular data of the Drinfel'd center of the given category. We consider two classes…

Category Theory · Mathematics 2019-12-25 Henry Tucker

We prove Clifford theoretic results on the representations of finite groups which only hold in characteristic $2$. Let $G$ be a finite group, let $N$ be a normal subgroup of $G$ and let $\varphi$ be an irreducible $2$-Brauer character of…

Representation Theory · Mathematics 2020-11-03 Rod Gow , John Murray

Recently, a new conjecture on the degrees of the irreducible Brauer characters of a finite group was presented by the second author. In this paper we propose a 'local' version of this conjecture for blocks B of finite groups, giving a lower…

Group Theory · Mathematics 2007-05-23 Thorsten Holm , Wolfgang Willems

In this article, we study the elements with disconnected centralizer in the Brauer complex associated to a simple algebraic group G defined over a finite field with corresponding Frobenius map F and derive the number of F-stable semisimple…

Representation Theory · Mathematics 2010-03-18 Olivier Brunat

We establish a formula for computing the unramified Brauer group of tame conic bundle threefolds in characteristic 2. The formula depends on the arrangement and residue double covers of the discriminant components, the latter being governed…

Algebraic Geometry · Mathematics 2018-06-18 Asher Auel , Alessandro Bigazzi , Christian Böhning , Hans-Christian Graf von Bothmer

We study Frobenius-Schur indicators of the regular representations of finite-dimensional semisimple Hopf algebras, especially group-theoretical ones. Those of various Hopf algebras are computed explicitly. In view of our computational…

Quantum Algebra · Mathematics 2010-10-21 Kenichi Shimizu