Algebra Seminar - R. L. Winter - Universiteit Leiden

Title: Density of rational points on a family of del Pezzo surfaces of degree 1.

Abstract:

Abstract: Del Pezzo surfaces are classified by their degree d, which is an integer between 1 and 9 (for d ≥ 3, these are the smooth surfaces of degree d in P^d). For del Pezzo surfaces of degree at least 2 over a field k, we know that the set of k-rational points is Zariski dense provided that the surface has one krational point to start with (that lies outside a specific subset of the surface for degree 2). However, for del Pezzo surfaces of degree 1 over a field k, even though we know that they always contain at least one k-rational point, we do not know if the set of k-rational points is Zariski dense in general. I will talk about a result that is joint work with Julie Desjardins, in which we give necessary and sufficient conditions for the set of k-rational points on a specific family of del Pezzo surfaces of degree 1 to be Zariski dense, where k is a number field. I will compare this to previous results.