Erratum to "On the 2 and the 3-Connectedness of ample divisors on a surface".
Estimates of the number of rational mappings from a fixed variety to varieties of general type
First we find effective bounds for the number of dominant rational maps between two fixed smooth projective varieties with ample canonical bundles. The bounds are of the type , where , is the canonical bundle of and are some constants, depending only on .Then we show that for any variety there exist numbers and with the following properties:For any threefold of general type the number of dominant rational maps is bounded above by .The number of threefolds , modulo birational...
Etale -covers in characteristic
Étude des fibrations elliptiques d’une surface
On s’intéresse aux fibrations elliptiques d’une surface singulière en vue de construire des courbes elliptiques avec torsion et rang sur .
Étude des surfaces algébriques
Étude des surfaces algébriques
Étude géométrique sur une question de licence
Even canonical surfaces with small - II
Even sets of nodes on sextic surfaces
We determine the possible even sets of nodes on sextic surfaces in , showing in particular that their cardinalities are exactly the numbers in the set . We also show that all the possible cases admit an explicit description. The methods that we use are an interplay of coding theory and projective geometry on one hand, and of homological and computer algebra on the other. We give a detailed geometric construction for the new case of an even set of 56 nodes, but the ultimate verification of existence...
Éventails et variétés toriques
Every rational surface is separably split.
Everywhere non reduced moduli spaces.
Examples of abelian surfaces in P4.
Examples of liftings of surfaces and a problem in de Rham cohomology
Examples of non-ample normal bundles
Examples of threefolds with Kodaira dimension 1 or 2
Exceptional Bundles On Nodal Enriques Surfaces.
Exceptional linear systems on curves on Del Pezzo surfaces.
Exceptional singular -homology planes
We consider singular -acyclic surfaces with smooth locus of non-general type. We prove that if the singularities are topologically rational then the smooth locus is - or -ruled or the surface is up to isomorphism one of two exceptional surfaces of Kodaira dimension zero. For both exceptional surfaces the Kodaira dimension of the smooth locus is zero and the singular locus consists of a unique point of type and respectively.
Existence and Degeneration of Kähler-Einstein Metrics on Minimal Algebraic Varieties of General Type.