Universal Chow group of zero-cycles on cubic hypersurfaces

Topology of Algebraic Varieties
Topic:Universal Chow group of zero-cycles on cubic hypersurfaces
Speaker:Claire Voisin
Affiliation:Centre national de la recherche scientifique; Distinguished Visiting Professor, School of Mathematics
Date:Wednesday, November 12
Time/Room:11:15am - 12:15pm/S-101
Video Link:http://video.ias.edu/tav/2014/1112-ClaireVoisin

We discuss the universal triviality of the \(\mathrm{CH}_0\)-group of cubic hypersurfaces, or equivalently the existence of a Chow-theoretic decomposition of their diagonal. The motivation is the study of stable irrationality for these varieties. Our main result is that this decomposition exists if and only if it exists on the cohomological level. As an application, we find that a cubic threefold has universally trivial \(\mathrm{CH}_0\) group if and only if the minimal class \(\theta^4/4!\) of its intermediate jacobian is the class of a 1-cycle (only twice this class is known to be algebraic).