Speaker: Mingmin Shen (University of Amsterdam, Netherlands) Date: 29/10/2021 at 10:30 Title: Some counter examples to the integral Hodge conjecture Abstract: I will explain how the integral Hodge conjecture fails on the product of a very general odd dimensional hypersurface and an Enriques surface. The proof uses a degeneration argument involving a careful analysis of vanishing cycles under base-change.