Seminar| Institute of Mathematical Sciences
Time：Monday, September 5th, 2022, 10:30-11:30
Location：R408, IMS
Speaker: ZiQuan Yang, Wisconsin-Madison
Abstract: The past decade has witnessed a great advancement on the Tate conjecture for varieties with Hodge number h^2,0 = 1. Charles, Madapusi-Pera and Maulik completely settled the conjecture for K3 surfaces over finite fields, and Moonen proved the Mumford-Tate (and hence also Tate) conjecture for more or less arbitrary h^2,0 = 1 varieties in characteristic 0.
In this talk, I will explain that the Tate conjecture is true for mod p reductions of complex projective h^2,0 = 1 varieties when p>>0, under a mild assumption on moduli. By refining this general result, we prove that in characteristic p ≥ 5 the BSD conjecture holds for a height 1 elliptic curve E over a function field of genus 1, as long as E is subject to the generic condition that all singular fibers in its minimal compacification are irreducible. We also prove the Tate conjecture over finite fields for a class of surfaces of general type and a class of Fano varieties. The overall philosophy is that the connection between the Tate conjecture over finite fields and the Lefschetz (1, 1)-theorem over C is very robust for h^2,0 = 1 varieties, and works well beyond the hyperkahler world.
This is based on joint work with Paul Hamacher and Xiaolei Zhao.