English
Related papers

Related papers: Block extensions, local categories, and basic Mori…

200 papers

In this brief postscript to our paper "Integral transforms and Drinfeld centers in derived algebraic geometry", we describe a Morita equivalence for derived, categorified matrix algebras implied by theory developed since its appearance. We…

Algebraic Geometry · Mathematics 2012-09-04 David Ben-Zvi , John Francis , David Nadler

We study the behavior of the Gorenstein weak global dimension under a cleft extension of rings; we prove that under some mild conditons the finiteness of the Gorenstein weak global dimension is invariant. Moreover, we compare the relative…

Category Theory · Mathematics 2025-09-29 Li Liang , Yajun Ma , Gang Yang

We show that the restricted Lie algebra structure on Hochschild cohomology is invariant under stable equivalences of Morita type between self-injective algebras. Thereby we obtain a number of positive characteristic stable invariants, such…

Representation Theory · Mathematics 2023-03-08 Benjamin Briggs , Lleonard Rubio y Degrassi

We prove that if $B$ is a $p$-block with non-trivial defect group $D$ of a finite $p$-solvable group $G$, then $\ell(B) < p^r$, where $r$ is the sectional rank of $D$. We remark that there are infinitely many $p$-blocks $B$ with non-Abelian…

Representation Theory · Mathematics 2016-11-08 Gunter Malle , Geoffrey R. Robinson

Let G be a (not necessarily Hausdorff) locally compact groupoid. We introduce a notion of properness for G, which is invariant under Morita-equivalence. We show that any generalized morphism between two locally compact groupoids which…

Operator Algebras · Mathematics 2007-05-23 Jean-Louis Tu

We define and study RoCK blocks for double covers of symmetric groups. We prove that RoCK blocks of double covers are Morita equivalent to standard `local' blocks. The analogous result for blocks of symmetric groups, a theorem of Chuang and…

Representation Theory · Mathematics 2022-12-01 Alexander Kleshchev , Michael Livesey

We give a general framework of equivariant model category theory. Our groups G, called Hopf groups, are suitably defined group objects in any well-behaved symmetric monoidal category V. For any V, a discrete group G gives a Hopf group,…

Algebraic Topology · Mathematics 2017-09-01 Bertrand Guillou , J. P. May , Jonathan Rubin

We show that if $B$ is a block of a finite group algebra $kG$ over an algebraically closed field $k$ of prime characteristic $p$ such that $\HH^1(B)$ is a simple Lie algebra and such that $B$ has a unique isomorphism class of simple…

Representation Theory · Mathematics 2016-11-28 Markus Linckelmann , Lleonard Rubio y Degrassi

Let $G$ be a countable group acting properly on a metric space with contracting elements and $\{H_i:1\le i\le n\}$ be a finite collection of Morse subgroups in $G$. We prove that each $H_i$ has infinite index in $G$ if and only if the…

Group Theory · Mathematics 2026-04-08 Zhenguo Huangfu , Renxing Wan

Let G be a finite group, let N be a normal subgroup of G, and let theta in Irr(N) be a G-invariant character. We fix a prime p, and we introduce a canonical partition of Irr(G|theta) relative to p. We call each member B_theta of this…

Representation Theory · Mathematics 2018-02-23 Noelia Rizo

We show how to extend a classic Morita Equivalence Result of Green's to the \cs-algebras of Fell bundles over transitive groupoids. Specifically, we show that if $p:\B\to G$ is a saturated Fell bundle over a transitive groupoid $G$ with…

Operator Algebras · Mathematics 2010-05-11 Marius Ionescu , Dana P. Williams

Let $G$ be a group and $\Bbbk$ a commutative ring. All categories and functors are assumed to be $\Bbbk$-linear. We define a $G$-invariant bimodule ${}_SM_R$ over $G$-categories $R, S$ and a $G$-graded bimodule ${}_BN_A$ over $G$-graded…

Representation Theory · Mathematics 2026-04-06 Hideto Asashiba , Shengyong Pan

We describe a general technique to classify blocks of finite groups, and we apply it to determine Morita equivalence classes of blocks with elementary abelian defect groups of order 32 with respect to a complete discrete valuation ring with…

Representation Theory · Mathematics 2021-01-25 Cesare Giulio Ardito

Let $G$ be a complex, connected, reductive algebraic group. In this paper we show analogues of the computations by Borho and MacPherson of the invariants and anti-invariants of the cohomology of the Springer fibres of the cone of nilpotent…

Representation Theory · Mathematics 2007-06-12 J. M. Douglass , G. Roehrle

We give a new proof, by using simplified terminology and notation, to a result of Puig stating that if a bimodule of two block algebras of finite groups over an algebraically closed field induces a stable equivalence of Morita type and has…

Representation Theory · Mathematics 2026-04-21 Xin Huang

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 this paper the authors investigate infinite-dimensional representations $L$ in blocks of the relative (parabolic) category ${\mathcal O}_S$ for a complex simple Lie algebra, having the property that the cohomology of the nilradical with…

Representation Theory · Mathematics 2007-05-23 Brian D. Boe , Markus Hunziker

We calculate the classical Iwasawa invariants of the Iwasawa modules associated to the $p$-adic topological $K$-theory of finite spectra. We show that the graded average of the orders of $n$ consecutive $K(1)$-local homotopy groups of a…

Algebraic Topology · Mathematics 2024-08-06 Austin Maison , Andrew Salch

A well-known result of Scopes states that there are only finitely many Morita equivalence classes of $p$-blocks of symmetric groups with a given weight (or defect). In this note we investigate a lower bound on the number of those Morita…

Representation Theory · Mathematics 2018-09-21 Benjamin Sambale

We give, in Sections 2 and 3, an english translation of: {\it Classes g\'en\'eralis\'ees invariantes}, J. Math. Soc. Japan, 46, 3 (1994), with some improvements and with notations and definitions in accordance with our book: {\it Class…

Number Theory · Mathematics 2021-08-24 Georges Gras