Séminaire de Géométrie
Negativity in the direct image of relative anti-canonical sheaf in families of Fano varieties
Behrouz Taji
( Sydney )Salle 2
le 23 mai 2025 à 10:45
It is well understood that positivity or negativity properties of canonical line bundle encode a significant amount of geometric data about the underlying projective variety. It is therefore unsurprising to expect that the same should be true for the relative canonical divisor of families of projective varieties. For families of varieties whose canonical divisor is ample (canonically polarized) or numerically trivial (Calabi-Yau), important positivity properties of the pushforward of the relative (pluri)canonical was discovered by Fujita, Kawamata, Kollár and Viehweg. Many fundamental results then followed as a consequence - from moduli theory of such varieties to birational geometry of base spaces of their degeneration. For families of Fano varieties however much less is known. In this talk I will discuss how one can complement some of these classical results in the Fano case. This is based on ongoing joint work with Sándor Kovács.