Algebra Seminar: McAndrew -- A descent theorem for K3 surfaces

Angus McAndrew is speaking in the Algebra Seminar this week.  We will go out for lunch
after the talk.  

When: Friday 5 May, 12-1pm 

Where: Carslaw 173 

Title: A descent theorem for K3 surfaces 

Abstract: Descent problems have fascinated mathematicians since ancient times.  A modern
descent question asks for the field of definition of a given algebraic variety, i.e.
whether there is a criterion for when it can be descended from a field to a smaller
one.  A theorem of Grothendieck gives an answer to this question in the case of abelian
varieties and transcendental field extensions.  We will discuss a general conjecture
inspired by this, and prove it in the case of K3 surfaces, under some hypotheses.  The
proof uses Madapusi-Pera’s work on the Kuga-Satake construction.