Lifting non-normal globally F-split surfaces from positive characteristic to the Witt vectors

Date/heure
26 mai 2025
14:00 - 15:00

Lieu
Salle de conférences Nancy

Oratrice ou orateur
Quentin Posva

Catégorie d'évènement
Séminaire de géométrie complexe


Résumé

It is well-known that not every variety in positive characteristic can be lifted to characteristic 0. However, it is conjectured that lifts exist for varieties on which the Frobenius map splits globally—the so-called globally F-split varieties. Recently, Bernasconi, Brivio, Kawakami and Witaszek established the following strong version in two dimension two: globally F-split normal surfaces indeed lift, together with their minimal resolution morphism. From the point of view of the MMP, it is natural to extend this result  to non-normal surfaces that are globally F-split.

In this talk, I will report on a joint project with F. Bernasconi, where we extend this strong lifting statement to non-normal globally F-split CY surfaces. Our argument involves a precise understanding of CY surface pairs with non-empty boundary, and some equivariant MMP.