Titres et résumés 2012 | UMR 5582 - Laboratoire de mathématiques

Dominique Cerveau

Title : Holomorphic foliations of codimension one, elementary theory

Abstract : In this introductory course I will present the basic notions, both local and global, using classical examples. I will explain statements in connection with the resolution of singularities with for instance the singular Frobenius Theorem or the Liouvilian integration. I will also present some open questions which I will motivate by examples.

Dans ce cours introductif je m’attacherai à présenter les notions de base tant locales que globales au travers d’exemples classiques. J’aborderai des énoncés liés à la résolution des singularités avec par exemple le théorème de Frobenius singulier ou l’intégration Liouvillienne. Je présenterai aussi quelques problèmes ouverts que je motiverai encore au travers d’exemples.

Jean-Pierre Demailly

Title : Kobayashi pseudo-metrics, entire curves and hyperbolicity of algebraic varieties

Abstract : We will first introduce the basic concepts pertaining to Kobayashi pseudo-distances and hyperbolic complex spaces, including Brody’s theorem and the Ahlfors-Schwarz lemma. One of the main goals of the theory is to understand conditions under which a given algebraic variety is Kobayashi hyperbolic. This leads to the introduction of jet spaces and jet metrics, and provides a strong link between the existence of entire curves and the existence of global algebraic differential equations.

Franc Forstnerič

Title : Non singular holomorphic foliations on Stein manifolds

Abstract : A nonsingular holomorphic foliation of codimension $q$ on a complex manifold $X$ is locally given by the level sets of a holomorphic submersion to the Euclidean space $\mathbb C^q$ . If $X$ is a Stein manifold, there also exist plenty of global foliations of this form, so long as there are no topological obstructions. More precisely, if $0< q < dim X$ then any $q$ -tuple of pointwise linearly independent (1,0)-forms can be continuously deformed to a $q$ -tuple of differentials $df_1,...,df_q$ where $f=(f_1,...,f_q)$ is a holomorphic submersion of $X$ to $\mathbb C^q$ . Such a submersion $f$ always exists if $q$ is no more than the integer part of $2n/3$ . More generally, if $E$ is a complex vector subbundle of the tangent bundle $TX$ such that $TX\backslash E$ is a flat bundle, then $E$ is homotopic (through complex vector subbundles of $TX$ ) to an integrable subbundle, i.e., to the tangent bundle of a nonsingular holomorphic foliation on $X$ . I will prove these results and discuss open problems, the most interesting one of them being related to a conjecture of Bogomolov.

Julien Duval

Title : Two results in almost complex hyperbolicity

Abstract : An almost complex manifold is hyperbolic if it does not contain any entire curve. We start characterizing hyperbolic compact almost complex manifolds. These are the ones whose holomorphic discs satisfy a linear isoperimetric inequality. Then we prove the almost complex version of the Greeene Theorem : the complementary of five lines in general position in a projective almost complex plane is hyperbolic.

Serguei Ivachkovitch

Title : Method of pseudoholomorphic curves and applications

Abstract : The method of « pseudoholomorphic » curves proved itself to be extremely useful in different fields. In symplectic topology, for instance Gromov’s Nonsqueezing Theorem, Arnold’s conjecture and the Floer homology, the Gromov-Witten invariants. In complex analysis and geometry, for instane polynomial hulls of totally real surfaces, envelopes of meromorphy, holomorphic foliations. We shall develop the theory of complex curves in almost complex manifolds and discuss some of these applications in our lectures.

Alexandre Sukhov

Title : J-complex curves : some applications

Abstract : We will focus in our lectures on the following : 1. J-complex discs in almost complex manifolds : general properties. Linearization and compactness. Gromov’s method : the Fredholm alternative for the d-bar operator. Attaching a complex disc to a Lagrangian manifold. Application : exotic symplectic structures. Hulls of totally real manifolds : Alexander’s theorem. 2. Real surfaces in (almost) complex surfaces. Filling real 2-spheres by a Levi-flat hypersurface (Bedford -Gaveau-Gromov theorem). Some applications. Symplectic and contact structures. Reeb foliation and the Weinsten conjecture. Hofer’s proof of the Weinstein conjecture. 3. J-complex lines and hyperbolicity. The KAM theory and Moser’s stability theorem for entire J-complex curves in tori. Global deformation and Bangert’s theorem.

François Lalonde

Title : Applications of Quantum homology to Symplectic Topology

Abstract : The first two lectures will present the fundamental results of symplectic topology : basic definitions, Moser’s lemma, normal forms of the symplectic structure near symplectic and Lagrangian submanifolds, characterization of Hamiltonian fibrations over any CW-complex. The third course will give the application of quantum homology to the splitting of the rational cohomology ring of any Hamiltonian fibration over S2, a generalization of a result of Deligne in the algebraic case and of Kirwan in the toric case. The fourth course will give the application of the quantum homology of a Lagrangian submanifold to the proof of the triviality of the monodromy of a weakly exact Lagrangian submanifold in any symplectic manifold.

Andrei Teleman

Title : Instantons and holomorphic curves on surfaces of class VII

Abstract : This series of lectures is dedicated to recent results concerning the existence of holomorphic curves on the surfaces of class VII. The first lecture will be an introduction to the Donaldson theory. We will present the fundamental notions and some important results in the theory, explaining ideas of the proofs. In the second lecture we will present the theory of holomorphic fiber bundles on complex surfaces, the stability notion, moduli spaces and the Kobayashi-Hitschin correspondence that links moduli spaces of stable fiber bundles (defined in the fram of complex geometry) to moduli spaces of instantons (defined in the frame of the Donaldson theory). In the last two lectures we will prove the existence of holomorphic curves on minimal surfaces of class VII with b2=1 or 2 and we will present the general strategy and the last results obtained in the general case.

Claude Viterbo

Title: Théorie des faisceaux et Topologie symplectique

Sheaf Theory and Symplectic Topology

Abstract : L’utilisation de méthodes de théorie des faisceaux (Kashiwara-Schapira)a été dévelopée ces dernières années par Tamarkin, Nadler, Zaslow, Guillermou, Kashiwara et Schapira. Nous essaierons d’en donner un aperçu à la fois pour démontrer des résultats classiques, comme la conjecture d’Arnold, et pour des résultats nouveaux.

The use of methods from the Sheaf Theory (Kashiwara-Schapira) was developped recently by Tamarkin, Nadler, Zaslow, Guillermou, Kashiwara and Schapira. We will try to give an insight of that, in order to prove classical results, such as the Arnold conjecture, and to obtain new results.