Foliations on Shimura varieties in positive characteristic
Abstract
This paper is a continuation of [G-dS1]. We study foliations of two types on Shimura varieties in characteristic . The first, which we call "tautological foliations", are defined on Hilbert modular varieties, and lift to characteristic . The second, the "-foliations", are defined on unitary Shimura varieties in characteristic only, and generalize the foliations studied by us before, when the CM field in question was quadratic imaginary. We determine when these foliations are -closed, and the locus where they are smooth. Where not smooth, we construct a "successive blow up" of our Shimura variety to which they extend as smooth foliations. We discuss some integral varieties of the foliations. We relate the quotient of by the foliation to a purely inseparable map from a certain component of another Shimura variety of the same type, with parahoric level structure at , to
Keywords
Cite
@article{arxiv.2205.00702,
title = {Foliations on Shimura varieties in positive characteristic},
author = {Eyal Z. Goren and Ehud de Shalit},
journal= {arXiv preprint arXiv:2205.00702},
year = {2023}
}
Comments
To appear in Journal of Algebraic Geometry. 1 figure