Principal bundles on toroidal compactifications of integral canonical models of abelian-type Shimura varieties
Peihang Wu
TL;DR
The paper addresses extending principal bundles and automorphic coefficient systems from noncompact integral canonical Shimura varieties to their toroidal compactifications at hyperspecial primes. It develops a comprehensive framework of canonical models and extensions for mixed and pure Shimura data, using tensor functors, boundary tensors, and Deligne induction, and then proves the existence and uniqueness of canonical extensions for abelian-type toroidal compactifications. Central contributions include the construction of a global canonical extension $\mathscr{E}^{\mathrm{can}}_{G^c}$ with compatible de Rham data, the demonstration of local freeness of boundary quotients, and the establishment of reduction and subcanonical extension mechanisms. These results provide robust integral models for automorphic bundles and their log connections, enabling arithmetic and cohomological investigations at the boundary and offering tools for coherent and log de Rham cohomology in the abelian-type setting.
Abstract
In this paper, we construct canonical extensions of principal $\mathcal{G}^c$- (and $M^c$-)bundles on toroidal compactifications of integral canonical models of abelian-type Shimura varieties with hyperspecial levels.
