# Events for 12/12/2018 from all calendars

## Colloquium - Felix Janda

**Time:** 4:00PM - 5:00PM

**Location:** BLOC 220

**Speaker:** Felix Janda, University of Michigan

**Description:** **Title:**Enumerative geometry: old and new.

**Abstract:**For as long as people have studied geometry, they have counted geometric objects. For example, Euclid's Elements starts with the postulate that there is exactly one line passing through two distinct points in the plane. Since then, the kinds of counting problems we are able to pose and to answer has grown. Today enumerative geometry is a rich subject with connections to many fields, including combinatorics, physics, representation theory, number theory and integrable systems. In this talk, I will show how to solve several classical counting questions. Then I will describe a more modern problem with roots in string theory which has been the subject of intense study for the last two decades, namely the study of the Gromov-Witten invariants of the quintic threefold, a Calabi-Yau manifold. I will explain a recent break-through in understanding the higher genus invariants that stems from a seemingly unrelated problem related to the study of holomorphic differentials on Riemann surfaces.