Calabi-Yau manifolds and a conjecture of Kobayashi.
Canonical models of surfaces of general type in positive characteristic
Canonical systems of double spaces.
Characteristic divisors on complex manifolds.
Characterizing Projective Bundles by Means of Ample Divisors.
Classes de cohomologie positives dans les variétés kählériennes compactes
Étant donnée une variété kählérienne compacte , on étudie dans l’espace vectoriel réel de cohomologie de Dolbeault le cône convexe des classes de Kähler ainsi que celui, plus grand, des classes de courants positifs fermés de type . Lorsque est projective, les traces de ces cônes sur l’espace de Néron–Severi engendré par les classes entières sont respectivement le cône des classes de diviseurs amples et l’adhérence de celui des classes de diviseurs effectifs.
Classifying Hilbert functions of fat point subschemes in P^2.
Clifford’s Theorem for real algebraic curves
We establish, for smooth projective real curves, an analogue of the classical Clifford inequality known for complex curves. We also study the cases when equality holds.
Codes de Goppa
Codimension Arithmetically Gorenstein Subschemes of projective -space
We study the lowest dimensional open case of the question whether every arithmetically Cohen–Macaulay subscheme of is glicci, that is, whether every zero-scheme in is glicci. We show that a general set of points in admits no strictly descending Gorenstein liaison or biliaison. In order to prove this theorem, we establish a number of important results about arithmetically Gorenstein zero-schemes in .
Comptage de courbes sur le plan projectif éclaté en trois points alignés
Nous établissons une version de la conjecture de Manin pour le plan projectif éclaté en trois points alignés, le corps de base étant un corps global de caractéristique positive.
Computing limit linear series with infinitesimal methods
Alexander and Hirschowitz determined the Hilbert function of a generic union of fat points in a projective space when the number of fat points is much bigger than the greatest multiplicity of the fat points. Their method is based on a lemma which determines the limit of a linear system depending on fat points approaching a divisor.Other Hilbert functions were computed previously by Nagata. In connection with his counter-example to Hilbert’s fourteenth problem, Nagata determined the Hilbert function...
Concerning the existence of nice components in the Hilbert scheme of curves in ...n for n = 4 and 5.
Configurations of - 2 Rational Curves on Sectional Surfaces of n-Folds.
Construction géométrique de la correspondance de McKay
Contractions of Gorenstein polarized varieties with high nef value.
Contractions of smooth varieties. II. Computations and applications
Una contrazione su una varietà proiettiva liscia è data da una mappa propria, suriettiva e a fibre connesse in una varietà irriducibile normale . La contrazione si dice di Fano-Mori se inoltre è -ampio. Nel lavoro, naturale seguito e completamento delle ricerche introdotte in [A-W3], si studiano diversi aspetti delle contrazioni di Fano-Mori attraverso esempi (capitolo 1) e teoremi di struttura (capitoli 3 e 4). Si discutono anche alcune applicazioni allo studio di morfismi birazionali propri...
Convex bodies associated to linear series
In his work on log-concavity of multiplicities, Okounkov showed in passing that one could associate a convex body to a linear series on a projective variety, and then use convex geometry to study such linear systems. Although Okounkov was essentially working in the classical setting of ample line bundles, it turns out that the construction goes through for an arbitrary big divisor. Moreover, this viewpoint renders transparent many basic facts about asymptotic invariants of linear series, and opens...
Correction to the gonality of smooth curves with plane models.
Corrections à l'article "Annulation du H1 et systèmes paracanoniques sur les surfaces".