Algebraic geometry seminar Day & Date: Monday, December 19, 2022. Time: 4 pm. Venue: Online talk at meet.google.com/vzr-ctov-kbs Title: Seshadri constants over fields of characteristic zero Speaker: Arghya Pramanik Abstract: Let X be a smooth projective variety defined over a field k of characteristic 0 and let L be a nef line bundle defined over k. In this talk, I will show that if x ∈ X is a k-rational point then the Seshadri constant ε(X, L, x) over \bar{k} is the same as that over k. I will also construct families of varieties whose global Seshadri constant ε(X) is zero. I also discuss a result on the existence of a Seshadri curve with a natural (and necessary) hypothesis. In a recent paper, Fulger and Murayama have defined a new version of Seshadri constants for vector bundles in a relative setting over algebraically closed fields. We generalize the definition for a general field and show that our results on line bundles are also true for vector bundles. This talk is based on joint work with Shripad M. Garge.