Speaker: Shinan Liu (TU Munich)

Date: January 24, 2019

Title: Local model of Hilbert-Siegel varieties in Gamma_1(p)-level

Abstract: In this talk, we consider the geometry of certain Shimura varieties with bad reduction. More precisely, we construct a local model for Hilbert-Siegel modular varieties with Gamma_1(p)-level structure. This generalizes the previous work on Siegel varieties by Haines-Stroh. Our key tool is a Zariski variant of Illusie’s fpqc ring-equivariant Lie complex of a group scheme. This enables us to calculate the Lie complex of the universal Raynaud group scheme on the Shimura variety, then to relate the integral model and the local model.