Faisceaux amples et très amples
Families of nets of low and medium strength.
Families of reduced zero-dimensional schemes.
A great deal of recent activity has centered on the question of whether, for a given Hilbert function, there can fail to be a unique minimum set of graded Betti numbers, and this is closely related to the question of whether the associated Hilbert scheme is irreducible or not. We give a broad class of Hilbert functions for which we show that there is no minimum, and hence that the associated Hilbert sheme is reducible. Furthermore, we show that the Weak Lefschetz Property holds for the general element...
Familles maximales de systèmes de ponts surabondants dans P2.
Fano manifolds of degree ten and EPW sextics
O’Grady showed that certain special sextics in called EPW sextics admit smooth double covers with a holomorphic symplectic structure. We propose another perspective on these symplectic manifolds, by showing that they can be constructed from the Hilbert schemes of conics on Fano fourfolds of degree ten. As applications, we construct families of Lagrangian surfaces in these symplectic fourfolds, and related integrable systems whose fibers are intermediate Jacobians.
Fibrés d'intersections et intégrales de classes de Chern
Fibrés vectoriels de rang 1 d'ordre fini
Fibrés vectoriels et cycles d'ordre fini sur une variété algébrique non compacte
Fibrés vectoriels topologiques de rang élevé sur une hypersurface
Fields of definition for some Hodge cycles.
Filtrations de Hodge et par l'ordre du pôle pour les hypersurfaces singulières
Filtrations on algebraic cycles and homology
Finiteness of cominuscule quantum -theory
The product of two Schubert classes in the quantum -theory ring of a homogeneous space is a formal power series with coefficients in the Grothendieck ring of algebraic vector bundles on . We show that if is cominuscule, then this power series has only finitely many non-zero terms. The proof is based on a geometric study of boundary Gromov-Witten varieties in the Kontsevich moduli space, consisting of stable maps to that take the marked points to general Schubert varieties and whose domains...
Finiteness theorems for algebraic cycles of small codimension on quadric fibrations over curves
We obtain finiteness theorems for algebraic cycles of small codimension on quadric fibrations over curves over perfect fields. For example, if k is finitely generated over ℚ and X → C is a quadric fibration of odd relative dimension at least 11, then CH i(X) is finitely generated for i ≤ 4.
Fonction de Seshadri arithmétique en géométrie d’Arakelov
To any adelic invertible sheaf on a projective arithmetic variety and any regular algebraic point of the arithmetic variety, we associate a function defined on which measures the separation of jets on this algebraic point by the “small” sections of the adelic invertible sheaf. This function will be used to study the arithmetic local positivity.
Fondements de la géométrie algébrique. Commentaires
Formal groups arising from algebraic varieties
Formal loops II : a local Riemann–Roch theorem for determinantal gerbes
Forme hermitienne canonique sur la cohomologie de la fibre de Milnor d'une hypersurface à singularité isolée.
Formes quadratiques et cycles algébriques
Introduite par Witt en 1937, la théorie des formes quadratiques sur un corps joue un rôle central dans la démonstration des conjectures de Milnor par Voevodsky via les travaux pionniers de Rost qui y interviennent. Réciproquement, les méthodes de Rost et Voevodsky utilisant la théorie des motifs et les opérations de Steenrod motiviques révolutionnent la théorie des formes quadratiques et ont conduit à la démonstration de résultats de base qui semblaient auparavant inaccessibles. On expliquera notamment...