On extensions of number fields obtained by specializing branched coverings.
On galois automorphisms of the fundamental group of the projective line minus three points.
On Galois covers of Hirzebruch surfaces.
On Galois module structure of the cohomology groups of an algebraic variety.
On ramified covers of the projective plane II: Generalizing Segre’s theory
The classical Segre theory gives a necessary and sufficient condition for a plane curve to be a branch curve of a (generic) projection of a smooth surface in . We generalize this result for smooth surfaces in a projective space of any dimension in the following way: given two plane curves, and , we give a necessary and sufficient condition for to be the branch curve of a surface in and to be the image of the double curve of a -model of . In the classical Segre theory, a plane curve...
On the Fundamental Group of a Unirational 3-Fold.
On the homotopy of the complement to plane algebraic curves.
On the intrinsic geometry of a unit vector field
We study the geometrical properties of a unit vector field on a Riemannian 2-manifold, considering the field as a local imbedding of the manifold into its tangent sphere bundle with the Sasaki metric. For the case of constant curvature , we give a description of the totally geodesic unit vector fields for and and prove a non-existence result for . We also found a family of vector fields on the hyperbolic 2-plane of curvature which generate foliations on with leaves of constant intrinsic...
On the period map for abelian covers of projective varieties
On the Ramification of Branched Coverings of IPn.
On the torsion free cover of the -module k
On the universal coverings of algebraic surfaces
On the vanishing of local homotopy groups for isolated singularities of complex spaces.
Pencils of irreducible rational curves and plane Jacobian conjecture
In certain cases the invertibility of a polynomial map F = (P,Q): ℂ²→ ℂ² can be characterized by the irreducibility and the rationality of the curves aP+bQ = 0, (a:b) ∈ ℙ¹.
Perverse sheaves with singularities along the curve Yn = Xm.
Points rationnels et groupes fondamentaux : applications de la cohomologie -adique
Je présenterai des résultats de T. Ekedahl et H. Esnault sur les variétés projectives lisses sur un corps de caractéristique strictement positive, disons , dont deux points peuvent être liés par une chaîne de courbes rationnelles, par exemple faiblement unirationnelles, ou de Fano. Notamment : 1) sur un corps fini, de telles variétés ont un point rationnel, résultat qui généralise le théorème de Chevalley-Warning ; 2) sur un corps algébriquement clos, de telles variétés ont un groupe fondamental...
Polynomial periodicity for Betti numbers of covering surfaces.
Projective embeddings of toric varieties
Quelques revetements définis sur Q.
Ramification divisors for branched coverings of IPn.