We endow the de Rham cohomology of any Poisson or Jacobi manifold with a natural homotopy Frobenius manifold structure. This result relies on a minimal model theorem for multicomplexes and a new kind of a Hodge degeneration condition.
We prove that the Hodge-de Rham spectral sequence for smooth proper tame Artin stacks in characteristic (as defined by Abramovich, Olsson, and Vistoli) which lift mod 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.
We study deformations of free and linear free divisors. We introduce a complex similar to the de Rham complex whose cohomology calculates the deformation spaces. This cohomology turns out to be zero for all reductive linear free divisors and to be constructible for Koszul free divisors and weighted homogeneous free divisors.
Let X be a separated scheme of finite type on a field k, the characteristic of k being assumed not equal to 2. We construct a duality for complexes of sheaves of Ox modules with maps differential operators of order ≤ 1. This theory is an extension of the theory built by R. Hartshorne for complexes with linear maps.
Soit une variété analytique complexe lisse et un diviseur libre. Les connexions logarithmiques intégrables par rapport à peuvent être étudiées comme des -modules localement libres munis d’une structure de module (à gauche) sur l’anneau des opérateurs différentiels logarithmiques . Dans cet article nous étudions deux résultats liés : la relation entre les duaux d’une connexion logarithmique intégrable sur les anneaux de base et , et un critère différentiel pour le théorème de comparaison...
In this paper the equality is established of three different pairings between the first de Rham cohomology group of an abelian scheme over a base flat over and that of its dual. These pairings have appeared and been used either explicitly or implicitly in the literature.In the last section we deduce a generalization to arbitrary characteristic of Serre’s formula for the Poincaré pairing on the first de Rham cohomology group of a curve over a field of characteristic zero.