Abstracts


K. Amerik
I am going to state the cone conjecture of Morrison and Kawamata for irreducible holomorphic symplectic manifolds, recently proved by Misha Verbitsky and myself, interpret it in terms of hyperbolic geometry and give a few applications, such as the finiteness of the number of birational models or the existence of nef line bundles
isotropic with respect to the Beauville-Bogomolov form.
A.Beauville
This is a survey of the progress obtained in the last 10 years on the Chow ring of projective hyperkäahler manifolds. Starting from the case of K3 surfaces, I will explain why one may hope that this Chow ring admits a natural grading. While this conjecture seems inaccessible at the moment, it implies some concrete consequences on intersections of divisors, which have been verified in an increasing number of cases.
F.Catanese
I shall report on some particular V(ariations of) H(odge) S(tructure) coming from integrals on cyclic coverings of the projective line. The first series leads to some counterexamples to a question raised by Fujita 30 years ago about semiampleness of the direct image of the relative canonical bundle (joint work with Dettweiler). These VHS come from interesting fibred surfaces, and I shall talk on work in progress about their geometry. The second one is a 2-parameter VHS leading to a ball quotient S discovered by Cartwright and Steger via computer calculations, and which has q=p_g=1. I shall describe the geometrical construction of  S as the covering of a Deligne-Mostow orbifold: this is joint work with Toledo, Stover and Keum.
K. Hulek
Cubic threefolds have played an important role in algebraic geometry since Clemens and Griffiths showed that these are unirational but not rational varieties. Their proof relies on a careful analysis of the intermediate Jacobians of cubic threefolds. In this talk I will discuss how the intermediate Jacobian degenerates when the cubic threefold takes on singularities such as A_n or D_n singularities. An important role in this analysis is played by the Fano surface of lines on cubic threefolds -- a topic which was also studied by W. Barth and A. Van den Ven. This is joint work with S. Casalaina-Martin, S. Grushevsky and R. Laza.
C. Peters
I explain by means of examples the role of  two central themes in van de Ven's work: vector bundles and complex surfaces. This talk is suited for mathematicians with little or no background in complex algebraic geometry.