Harvard-MIT Algebraic Geometry Seminar: Superadditivity of anticanonical Iitaka dimension in positive characteristic


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November 14, 2023 3:00 pm - 4:00 pm
Science Center 507
Address: 1 Oxford Street, Cambridge, MA 02138 USA

Iacopo Brivio - CMSA

Given a fibration $f\colon X\to Y$ of smooth complex projective with general fiber $F$, the celebrated Iitaka conjecture predicts the inequality $\kappa(K_X)\geq \kappa(K_F)+\kappa(K_Y)$. Recently Chang showed that, under some natural conditions, the inequality $\kappa(-K_X)\leq \kappa(-K_F)+\kappa(-K_Y)$ holds.

In this talk I will show that, despite the failure in positive characteristic of both the Iitaka conjecture and Chang's theorem, it is possible to recover the latter for "tame" positive characteristic fibrations. This is based on joint work with M. Benozzo and C.-K. Chang.

For more information, please see https://researchseminars.org/seminar/harvard-mit-ag-seminar