Vanishing criteria and the Picard group for projective varieties of low codimension
Vanishing cycles, the generalized Hodge Conjecture and Gröbner bases
Let X be a general complete intersection of a given multi-degree in a complex projective space. Suppose that the anti-canonical line bundle of X is ample. Using the cylinder homomorphism associated with the family of complete intersections of a smaller multi-degree contained in X, we prove that the vanishing cycles in the middle homology group of X are represented by topological cycles whose support is contained in a proper Zariski closed subset T of X with certain codimension. In some cases, by...
Vanishing lattices and monodromy groups of isolated com-plete intersection singularities.
Vanishing of Cotangent Functors.
Vanishing of sections of vector bundles on 0-dimensional schemes
Here we give conditions and examples for the surjectivity or injectivity of the restriction map , where is a projective variety, is a vector bundle on and is a “general” -dimensional subscheme of , union of general “fat points”.
Vanishing theorems and degeneracy loci in small corang. (Théoremès d'annulation et lieux de degenerescence en petit corang.)
Vanishing theorems, linear and quadratic normality.
Variation of the divisor class group.
Varieities with low dimensional dual variety.
Variétés de codimension dans
Variétés de drapeaux et réseaux de Toda.
Variétés de Prym et jacobiennes intermédiaires
Variétés horosphériques de Fano
Une variété horosphérique est une variété algébrique normale dans laquelle un groupe algébrique réductif opère avec une orbite ouverte fibrée en tores sur une variété de drapeaux. En particulier, les variétés toriques et les variétés de drapeaux sont horosphériques. Dans cet article, on classifie les variétés horosphériques de Fano en termes de certains polytopes rationnels qui généralisent les polytopes réflexifs considérés par V. Batyrev. Puis on obtient une majoration du degré des variétés horosphériques...
Variétés rationnellement connexes
Variétés stablement rationnelles non rationnelles
Variétés unirationnelles non rationnelles
Variétés unirationnelles non rationnelles: au-delà de l'example d'Artin et Mumford.
Varieties of minimal rational tangents of codimension 1
Let be a uniruled projective manifold and let be a general point. The main result of [2] says that if the -degrees (i.e., the degrees with respect to the anti-canonical bundle of ) of all rational curves through are at least , then is a projective space. In this paper, we study the structure of when the -degrees of all rational curves through are at least . Our study uses the projective variety , called the VMRT at , defined as the union of tangent directions to the rational curves...
Varieties of modules over tubular algebras
We classify the irreducible components of varieties of modules over tubular algebras. Our results are stated in terms of root combinatorics. They can be applied to understand the varieties of modules over the preprojective algebras of Dynkin type 𝔸₅ and 𝔻₄.
Varieties with many lines.