Let K be a finite extension of p-adic numbers. We investigate the ramification in the cohomology of a K3 surface over K, under the assumption that X admits an integral model whose special fibre has at worst ordinary double points. We will determine the ramification in the cohomology of X in terms of a numerical invariant of the integral model. As an application, we determine the action of the inertia group on the primitive cohomology of certain lattice-polarized K3 surfaces.

### Algebra Seminar

Monday, March 27, 2017 - 3:15pm

#### Dohyeong Kim

University of Michigan