On the fundamental group of the complement of a divisor in a homogeneous space.
On the Fundamental Group of the Space of Cubic Surfaces.
On the fundamental groups of some open rational surfaces.
On the Gauss maps of space curves in characteristic p
On the Gauss maps of space curves in characteristic p, II
On the general hyperplane section of a projective curve.
On the generalized theta divisor.
On the generalized vanishing conjecture
We show that the GVC (generalized vanishing conjecture) holds for the differential operator and all polynomials , where is any polynomial over the base field. The GVC arose from the study of the Jacobian conjecture.
On the generation of certain bundles over P3.
On the generic injectivity of the Gauss map in positive characteristic.
On the genus of reducible surfaces and degenerations of surfaces
We deal with a reducible projective surface with so-called Zappatic singularities, which are a generalization of normal crossings. First we compute the -genus of , i.e. the dimension of the vector space of global sections of the dualizing sheaf . Then we prove that, when is smoothable, i.e. when is the central fibre of a flat family parametrized by a disc, with smooth general fibre, then the -genus of the fibres of is constant.
On the Genus of Varieties of Codimension 2 in Projective Space.
On the Geography of Surfaces. Simply Connected Minimal Surfaces with Positive Index.
On the Geometrie Genera of Projective Curves.
On the Geometry of a Siegel Modular Threefold.
On the geometry of a special determinantal hypersurface associated to the Mumford-Horrocks vector bundle.
On the geometry of algebraic curves having many real components.
We show that there is a large class of nonspecial effective divisors of relatively small degree on real algebraic curves having many real components i.e. on M-curves. We apply to 1. complete linear systems on M-curves containing divisors with entirely real support, and 2. morphisms of M-curves into P1.
On the geometry of conjugacy classes in classical groupes.
On the geometry of moduli of curves and line bundles
Here we focus on the geometry of , the compactification of the universal Picard variety constructed by L. Caporaso. In particular, we show that the moduli space of spin curves constructed by M. Cornalba naturally injects into and we give generators and relations of the rational Picard group of , extending previous work by A. Kouvidakis.
On the geometry of null cones in Einstein-vacuum spacetimes