# セミナー

## 代数セミナー

タイトル Quasi-Frobenius-split and Serre-Tate theory 2019年11月27日 16:30-17:30 呼子 笛太郎 氏 (名古屋大学) 矢上キャンパス 14棟631A/B室 This is a work in progress. According to the Serre-Tate theory, the local moduli space of ordinary abelian varieties or $K3$ surfaces has canonical coordinates, in particular, an ordinary variety admits a canonical lift to characteristic $0$. It is known that, for a Calabi-Yau variety in positive characteristic, ordinarity is equivalent to Frobenius-splitting. Recently, Achinger and Zdanowicz constructed the canonical lift modulo $p^2$ using Frobenius-splitting and mentioned that the method works for quasi-Frobenius-split schemes. In this talk, I will explain a deformation theoretic aspect of their construction and investigate the local moduli of a finite height $K3$ surface.