26 mar 2015 -- 16:00
Aula 211, Dip. Matematica, Università "Roma Tre", Roma
In this talk I will showcase a general class of smooth rational cubic fourfolds X containing a plane whose associated quadric surface bundle does not have a rational section. Equivalently, the Brauer class B of the even Clifford algebra over the discriminant cover (a K3 surface S of degree 2) associated to the quadric bundle, is nontrivial. These fourfolds provide nontrivial examples verifying Kuznetsov's conjecture on the rationality of cubic fourfolds containing a plane. I will then explore the connections between this construction and the existence of one-apparent-double-point surfaces inside the cubic 4fold.