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Given a positive integer $u$ and a simple algebraic group $G$ defined over an algebraically closed field $K$ of characteristic $p$, we derive properties about the subvariety $G_{[u]}$ of $G$ consisting of elements of $G$ of order dividing…

Group Theory · Mathematics 2017-06-07 Claude Marion

Relying on the classification of the indecomposable liftable modules in arbitrary blocks with non-trivial cyclic defect groups we give a complete classification of the trivial source modules lying in such blocks, describing in particular…

Representation Theory · Mathematics 2020-04-08 Gerhard Hiss , Caroline Lassueur

This work provides five explicit constructions of the exceptional Lie algebra $\mathfrak{e}_8$, based on its semisimple subalgebras of maximal rank. Each of these models is graded by an abelian group, namely, $\mathbb{Z}_4$, $\mathbb{Z}_5$,…

Rings and Algebras · Mathematics 2025-08-12 Yolanda Cabrera , Cristina Draper , Antonio Garvin

A quasi-representation of a group is a map from the group into a matrix algebra (or similar object) that approximately satisfies the relations needed to be a representation. Work of many people starting with Kazhdan and Voiculescu, and…

Group Theory · Mathematics 2026-05-25 Rufus Willett

In this paper, we investigate the block that has an abelian defect group of rank $2$ and its Brauer correspondent has only one simple module. We will get an isotypy between the block and its Brauer correspondent. It will generalize the…

Group Theory · Mathematics 2019-09-20 Xueqin Hu

We formulate and classify super Satake diagrams under a mild assumption, building on arbitrary Dynkin diagrams for finite-dimensional basic Lie superalgebras. We develop a theory of quantum supersymmetric pairs associated to the super…

Quantum Algebra · Mathematics 2025-08-25 Yaolong Shen , Weiqiang Wang

Let X be a smooth double cover of a geometrically ruled surface defined over a separably closed field of characteristic different from 2. The main result of this paper is a finite presentation of the 2-torsion in the Brauer group of X with…

Number Theory · Mathematics 2015-12-18 Brendan Creutz , Bianca Viray

Fundamental conjectures in modular representation theory of finite groups, more precisely, Alperin's Weight Conjecture and Robinson's Ordinary Weight Conjecture, can be expressed in terms of fusion systems. We use fusion systems to connect…

Representation Theory · Mathematics 2023-11-23 Radha Kessar , Gunter Malle , Jason Semeraro

In 1971, Kac and Weisfeiler made two influential conjectures describing the dimensions of simple modules of a restricted Lie algebra $\mathfrak{g}$. The first predicts the maximal dimension of simple $\mathfrak{g}$-modules and in this paper…

Representation Theory · Mathematics 2019-01-29 Benjamin Martin , David Stewart , Akaki Tikaradze , Lewis Topley

Let f be a newform of weight 2k-2 and level 1. In this paper we provide evidence for the Bloch-Kato conjecture for modular forms. We demonstrate an implication that under suitable hypothesis if a prime divides the algebraic part of L(k,f),…

Number Theory · Mathematics 2007-05-23 Jim Brown

We classify principal blocks of finite groups with semidihedral defect groups up to splendid Morita equivalence. This completes the classification of all principal $2$-blocks of tame representation type up to splendid Morita equivalence and…

Representation Theory · Mathematics 2020-10-19 Shigeo Koshitani , Caroline Lassueur , Benjamin Sambale

By the reduction theorems of Navarro--Tiep and Sp\"ath, a way to prove the Alperin weight conjecture and its blockwise version is to verify the co-called inductive Alperin weight condition and inductive blockwise Alperin weight condition…

Representation Theory · Mathematics 2021-04-01 Zhicheng Feng , Conghui Li , Jiping Zhang

For a $p$-permutation equivalence between two block algebras of finite groups, we introduce new square diagrams that link the $p$-permutation equivalence via the Brauer construction to local equivalences between stabilizers of corresponding…

Representation Theory · Mathematics 2025-12-23 Robert Boltje , John Revere McHugh

We provide an algorithm for calculating the unramified Brauer group of a homogeneous space $X$ of a semi-simple simply connected group $H$ with finite geometric stabiliser over any field of characteristic 0. When $k$ is a number field, we…

Algebraic Geometry · Mathematics 2025-06-04 Lucas Lagarde

H. Miyachi and W. Turner have independently proved that Broue's Abelian Defect Group Conjecture holds for certain unipotent blocks of the finite general linear group, the so-called Rouquier blocks. This together with A. Marcus and J. Chuang…

Representation Theory · Mathematics 2012-10-09 Michael Livesey

The main result describes the Brauer-Nesbitt reduction of unipotent representations of a finite group of Lie type, expressing it as an explicit linear combination of the restriction of Weyl modules from the algebraic group to the group of…

Representation Theory · Mathematics 2026-04-01 Roman Bezrukavnikov , Michael Finkelberg , David Kazhdan , Calder Morton-Ferguson

Let $\Gamma\subset \bar{\mathbb{Q}}^*$ be a finitely generated subgroup. Denote by $\Gamma_\mathrm{div}$ its division group. A recent conjecture due to R\'emond, related to the Zilber-Pink conjecture, predicts that the absolute logarithmic…

Number Theory · Mathematics 2023-02-13 Arnaud Plessis

We prove a conjecture of Broue about the Jordan decomposition of blocks of finite reductive groups. We show that a block of a finite connected reductive group, in non-describing characteristic, is Morita-equivalent to a quasi-isolated block…

Representation Theory · Mathematics 2007-05-23 Cedric Bonnafe , Raphael Rouquier

We propose two definitions of configuration Lie groupoids and in both the cases we prove a Fadell-Neuwirth type fibration theorem for a class of Lie groupoids. We show that this is the best possible extension, in the sense that, for the…

Geometric Topology · Mathematics 2025-08-08 S K Roushon

Using a stable equivalence due to Rouquier, we prove that Broue's abelian defect group conjecture holds for 3-blocks of defect 2 whose Brauer correspondent has a unique isomorphism class of simple modules. The proof makes use of the fact,…

Group Theory · Mathematics 2014-02-26 Radha Kessar