Algebraic Geometry Seminar: "A pencil of Enriques surfaces with non-algebraic integral Hodge classes"

Abstract: In this talk, we exhibit a pencil of Enriques surfaces defined over Q with non-algebraic integral Hodge classes of non-torsion type. This gives the first example of a threefold with trivial Chow group of zero-cycles on which the integral Hodge conjecture fails. As an application, we construct a fourfold which gives the negative answer to a classical question posed by Murre on the universality of the Abel-Jacobi maps in codimension three. This is joint work with John Christian Ottem.

Host: Matt Kerr