Séminaire de l’équipe AGA
Responsables : F. SCAVIA, M. TAMIOZZO
Vendredi 12 juin 2026
10:30 Fabio Bernasconi (Sapienza Università di Roma) 
Résumé
3-dimensional del Pezzo fibrations in positive characteristic
Salle B407, bâtiment B, LAGA, Institut Galilée, Université Paris 13The Minimal Model Program (MMP) is an algorithm that aims to find a distinguished representative for a variety over a field k within its birational class. In dimension 3, one of the possible outcomes of the MMP is a del Pezzo fibration over a curve. If k has positive characteristic, additional complications arise: generic smoothness fails in general, and all fibers can be extremely singular. For this reason, it is better to study the generic fiber of the fibration, which is a regular del Pezzo surface defined over an imperfect field. Motivated by this, we extend classical results due to Enriques, Manin, and Iskovskikh regarding the rationality and existence of rational points for such surfaces to the imperfect case, and apply them to 3-folds. This is joint work with H. Tanaka.
Vendredi 19 juin 2026
09:00 M. Dimitrov, M. Harris, H. Hida, V. Pilloni, E. Urban () Résumé
Journée arithmétique du LAGA (en l'honneur de Jacques Tilouine)
Amphithéâtre Becquerel
