# Events for 02/04/2019 from all calendars

## Student Working Seminar in Groups and Dynamics

**Time:** 2:00PM - 3:00PM

**Location:** BLOC 628

**Speaker:** Nicolas Matte Bon, ETH Zurich

**Title:** *An introduction to group actions on the circle be homeomorphism*

## Geometry Seminar

**Time:** 3:00PM - 5:00PM

**Location:** BLOC 628

**Speaker:** C.J. Bott, TAMU

**Title:** *Mirror symmetry for K3 surfaces*

**Abstract:** Mirror symmetry is the phenomenon, originally discovered by physicists, that Calabi-Yau manifolds come in dual pairs, with each member of the pair producing the same physics. Mathematicians studying enumerative geometry became interested in mirror symmetry around 1990, and since then, mirror symmetry has become a major research topic in pure mathematics. One important problem in mirror symmetry is that there may be several ways to construct a mirror dual for a Calabi-Yau manifold. Hence it is a natural question to ask: when two different mirror symmetry constructions apply, do they agree? We specifically consider two mirror symmetry constructions for K3 surfaces known as BHK and LPK3 mirror symmetry. BHK mirror symmetry was inspired by the Landau-Ginzburg/Calabi-Yau correspondence, while LPK3 mirror symmetry is more classical. In particular, for algebraic K3 surfaces with a purely non-symplectic automorphism of order n, we ask if these two constructions agree. Results of Artebani-BoissiÃ¨re-Sarti (2011) originally showed that they agree when n=2, and Comparin-Lyon-Priddis-Suggs (2012) showed that they agree when n is prime. However, the n being composite case required more sophisticated methods. Whenever n is not divisible by four (or n=16), this problem was solved by Comparin and Priddis (2017) by studying the associated lattice theory more carefully. We complete the remaining case of the problem when n is divisible by four by finding new isomorphisms and deformations of the K3 surfaces in question, develop new computational methods, and use these results to complete the investigation, thereby showing that the BHK and LPK3 mirror symmetry constructions also agree when n is composite.