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Related papers: Perverse Equivalences and Brou\'e's Conjecture

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In this paper we prove equivalences of categories relating the derived category of a block of the category of representations of a connected reductive algebraic group over an algebraically closed field of characteristic $p$ bigger than the…

Representation Theory · Mathematics 2018-04-13 Pramod N. Achar , Simon Riche

We investigate permutations in terms of their cycle structure and descent set. To do this, we generalize the classical bijection of Gessel and Reutenauer to deal with permutations that have some ascending and some descending blocks. We then…

Combinatorics · Mathematics 2009-09-01 Jacob Steinhardt

We define a quantum analogue of the Grothendieck ring of finite dimensional modules of a quantum affine algebra of simply laced type. The construction is based on perverse sheaves on a variety related to quivers. We get also a new geometric…

Quantum Algebra · Mathematics 2007-05-23 Michela Varagnolo , Eric Vasserot

A new type of conjectures on characters of finite groups, related to the McKay conjecture, have recently been proposed. In this paper, we study these conjectures for symmetric groups.

Group Theory · Mathematics 2026-02-11 Juan Martínez Madrid

Chuang and Rouquier describe an action by perverse equivalences on the set of bases of a triangulated category of Calabi-Yau dimension $-1$. We develop an analogue of their theory for Calabi-Yau categories of dimension $w<0$ and show it is…

Representation Theory · Mathematics 2020-01-03 Jeremy Brightbill

We give a reduction to quasisimple groups for Donovan's conjecture for blocks with abelian defect groups defined with respect to a suitable discrete valuation ring $\mathcal{O}$. Consequences are that Donovan's conjecture holds for…

Representation Theory · Mathematics 2019-05-27 Charles W. Eaton , Florian Eisele , Michael Livesey

Let $K$ be a normal subgroup of the finite group $H$. To a block of a $K$-interior $H$-algebra we associate a group extension, and we prove that this extension is isomorphic to an extension associated to a block given by the Brauer…

Representation Theory · Mathematics 2011-12-02 Tiberiu Coconet

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

Let X be a scheme of finite type over a Noetherian base scheme S admitting a dualizing complex, and let U be an open subset whose complement has codimension at least 2. We extend the Deligne-Bezrukavnikov theory of perverse coherent sheaves…

Representation Theory · Mathematics 2017-01-03 Pramod N. Achar , Daniel S. Sage

The most developed aspect of the theory of finite semigroups is their classification in pseudovarieties. The main motivation for investigating such entities comes from their connection with the classification of regular languages via…

Group Theory · Mathematics 2025-04-14 Jorge Almeida

Eaton and Moret\'o proposed an extension of Brauer's famous height zero conjecture on blocks of finite groups to the case of non-abelian defect groups, which predicts the smallest non-zero height in such blocks in terms of local data. We…

Representation Theory · Mathematics 2014-05-16 Olivier Brunat , Gunter Malle

We consider a fixed block for the equivariant perverse sheaves with nilpotent support in the $1$-graded ccomponent of a semisimple cyclically graded Lie algebra. We give a combinatorial parametrization of the simple objects in that block.

Representation Theory · Mathematics 2016-10-03 George Lusztig , Zhiwei Yun

This series of papers is a contribution to the program of classifying $p$-blocks of finite groups up to source algebra equivalence, starting with the case of cyclic blocks. To any $p$-block $\mathbf{B}$ of a finite group with cyclic defect…

Representation Theory · Mathematics 2026-01-06 Gerhard Hiss , Caroline Lassueur

In a paper of 2003, B. K\"ulshammer, J. B. Olsson and G. R. Robinson defined $\ell$-blocks for the symmetric groups, where $\ell >1$ is an arbitrary integer. In this paper, we give a definition for the defect group of the principal…

Representation Theory · Mathematics 2014-02-26 Jean-Baptiste Gramain

We discuss the classical statement of group classification problem and some its extensions in the general case. After that, we carry out the complete extended group classification for a class of (1+1)-dimensional nonlinear…

Mathematical Physics · Physics 2010-11-03 N. M. Ivanova , R. O. Popovych , C. Sophocleous

We consider categories of generalized perverse sheaves, with relaxed constructibility conditions, by means of the process of gluing $t$-structures and we exhibit explicit abelian categories defined in terms of standard sheaves categories…

Algebraic Geometry · Mathematics 2007-05-23 F. Gudiel-Rodriguez , L. Narvaez-Macarro

We propose new conjectures about the relationship between the principal blocks of finite groups for different primes and establish evidence for these conjectures.

Group Theory · Mathematics 2022-04-08 Gabriel Navarro , Noelia Rizo , A. A. Schaeffer Fry

To every minimal model of a complete local isolated cDV singularity Donovan--Wemyss associate a finite dimensional symmetric algebra known as the contraction algebra. We construct the first known standard derived equivalences between these…

Representation Theory · Mathematics 2020-02-11 Jenny August

Trinh and Xue have proposed a startling conjecture on intersections of blocks of cyclotomic Hecke algebras occurring in modular representation theory of finite reductive groups. We prove this conjecture for all exceptional type groups apart…

Representation Theory · Mathematics 2026-03-10 Maria Chlouveraki , Gunter Malle

We give a complete description of the Morita equivalence classes of blocks with elementary abelian defect groups of order 8 and of the derived equivalences between them. A consequence is the verification of Brou\'e's abelian defect group…

Representation Theory · Mathematics 2014-09-23 Charles W. Eaton