Cycles on splitting models of Shimura varieties

Fuente: arXiv
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Auteur principal: Hove, Thibaud van den
Format: Preprint
Publié: 2026
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author Hove, Thibaud van den
author_facet Hove, Thibaud van den
contents We construct exotic Hecke correspondences between the special fibers of different PEL type Shimura varieties, when the local groups are restrictions of scalars of unramified groups. In particular, the local groups themselves are not necessarily unramified, and the Shimura varieties can have bad reduction. By adapting the methods of Xiao-Zhu in the case of good reduction, we use this to construct new instances of the geometric Jacquet-Langlands correspondence, including a motivic refinement, and verify generic instances of the Tate conjecture for the special fibers of these Shimura varieties at very special level. Our main tool is to resolve the integral models by the splitting models of Pappas-Rapoport. We also define splitting versions of the moduli stacks of local shtukas and affine Deligne-Lusztig varieties, and study their geometry.
format Preprint
id arxiv_https___arxiv_org_abs_2603_08870
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Cycles on splitting models of Shimura varieties
Hove, Thibaud van den
Algebraic Geometry
Number Theory
Representation Theory
We construct exotic Hecke correspondences between the special fibers of different PEL type Shimura varieties, when the local groups are restrictions of scalars of unramified groups. In particular, the local groups themselves are not necessarily unramified, and the Shimura varieties can have bad reduction. By adapting the methods of Xiao-Zhu in the case of good reduction, we use this to construct new instances of the geometric Jacquet-Langlands correspondence, including a motivic refinement, and verify generic instances of the Tate conjecture for the special fibers of these Shimura varieties at very special level. Our main tool is to resolve the integral models by the splitting models of Pappas-Rapoport. We also define splitting versions of the moduli stacks of local shtukas and affine Deligne-Lusztig varieties, and study their geometry.
title Cycles on splitting models of Shimura varieties
topic Algebraic Geometry
Number Theory
Representation Theory
url https://arxiv.org/abs/2603.08870