On certain integral Frobenius period maps for Shimura varieties and their reductions

Abstract

We formulate an integral Frobenius period map for the framed crystalline prismatization of the $p$-integral model $\mathcal{S}$ of a Shimura variety with good reduction. By analyzing reductions of this map, we derive a period map from the mod $p$ fiber $S$ of $\mathcal{S}$ to the moduli stack of 1-1 truncated local $G$-shtukas in the prismatic topology, which refines the zip period map of $S$ within this topology. Furthermore, we show that the pair $(\mathcal{S},S)$ is associated with a double $G$-zip. Additionally, we introduce a framework of base reduction diagrams.

Revised for clarity and conciseness; main results unchanged