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de Rham Theory for Tame Stacks and Schemes with Linearly Reductive Singularities

Matthew Satriano (2012)

Annales de l’institut Fourier

We prove that the Hodge-de Rham spectral sequence for smooth proper tame Artin stacks in characteristic p (as defined by Abramovich, Olsson, and Vistoli) which lift mod p 2 degenerates. We push the result to the coarse spaces of such stacks, thereby obtaining a degeneracy result for schemes which are étale locally the quotient of a smooth scheme by a finite linearly reductive group scheme.

Decomposability criterion for linear sheaves

Marcos Jardim, Vitor Silva (2012)

Open Mathematics

We establish a decomposability criterion for linear sheaves on ℙn. Applying it to instanton bundles, we show, in particular, that every rank 2n instanton bundle of charge 1 on ℙn is decomposable. Moreover, we provide an example of an indecomposable instanton bundle of rank 2n − 1 and charge 1, thus showing that our criterion is sharp.

Décomposition du Galois-module des entiers d'une extension cyclique de degré premier d'un corps de nombres ou d'un corps local

Françoise Bertrandias (1979)

Annales de l'institut Fourier

Soit A un anneau de Dedekind, de corps des fractions K , et soit L une extension galoisienne de K , dont le groupe de Galois G est cyclique d’ordre premier. On note B la clôture intégrale de A dans L . Il existe une unique décomposition du A [ G ] -module B en somme directe de sous-modules indécomposables. On détermine cette décomposition lorsque K est un corps local ou un corps de nombres. Le résultat dépend d’une part des caractères irréductibles de G sur K , d’autre part des nombres de ramification associés...

Decomposition into special cubes and its applications to quasi-subanalytic geometry

Krzysztof Jan Nowak (2009)

Annales Polonici Mathematici

The main purpose of this paper is to present a natural method of decomposition into special cubes and to demonstrate how it makes it possible to efficiently achieve many well-known fundamental results from quasianalytic geometry as, for instance, Gabrielov's complement theorem, o-minimality or quasianalytic cell decomposition.

Decomposition numbers for perverse sheaves

Daniel Juteau (2009)

Annales de l’institut Fourier

The purpose of this article is to set foundations for decomposition numbers of perverse sheaves, to give some methods to calculate them in simple cases, and to compute them concretely in two situations: for a simple (Kleinian) surface singularity, and for the closure of the minimal non-trivial nilpotent orbit in a simple Lie algebra.This work has applications to modular representation theory, for Weyl groups using the nilpotent cone of the corresponding semisimple Lie algebra, and for reductive...

Decompositions of an Abelian surface and quadratic forms

Shouhei Ma (2011)

Annales de l’institut Fourier

When a complex Abelian surface can be decomposed into a product of two elliptic curves, how many decompositions does the Abelian surface admit? We provide arithmetic formulae for the number of such decompositions.

Decompositions of hypersurface singularities oftype J k , 0

Piotr Jaworski (1994)

Annales Polonici Mathematici

Applications of singularity theory give rise to many questions concerning deformations of singularities. Unfortunately, satisfactory answers are known only for simple singularities and partially for unimodal ones. The aim of this paper is to give some insight into decompositions of multi-modal singularities with unimodal leading part. We investigate the J k , 0 singularities which have modality k - 1 but the quasihomogeneous part of their normal form only depends on one modulus.

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