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Bibliographic Details
Main Author: van Hoften, Pol
Format: Preprint
Published: 2019
Subjects:
Online Access:https://arxiv.org/abs/1906.04008
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author van Hoften, Pol
author_facet van Hoften, Pol
contents We study the Picard-Lefschetz formula for the Siegel modular threefold of paramodular level and prove the weight-monodromy conjecture for its middle degree inner cohomology with arbitrary automorphic coefficients. We give some applications to the Langlands programme: Using Rapoport-Zink uniformisation of the supersingular locus of the special fiber, we construct a geometric Jacquet-Langlands correspondence between $\operatorname{GSp}_4$ and a definite inner form, proving a conjecture of Ibukiyama. We also prove an integral version of the weight-monodromy conjecture and use it to deduce a level lowering result for cohomological cuspidal automorphic representations of $\operatorname{GSp}_4$.
format Preprint
id arxiv_https___arxiv_org_abs_1906_04008
institution arXiv
publishDate 2019
record_format arxiv
spellingShingle A geometric Jacquet-Langlands correspondence for paramodular Siegel threefolds
van Hoften, Pol
Number Theory
Algebraic Geometry
11G18
We study the Picard-Lefschetz formula for the Siegel modular threefold of paramodular level and prove the weight-monodromy conjecture for its middle degree inner cohomology with arbitrary automorphic coefficients. We give some applications to the Langlands programme: Using Rapoport-Zink uniformisation of the supersingular locus of the special fiber, we construct a geometric Jacquet-Langlands correspondence between $\operatorname{GSp}_4$ and a definite inner form, proving a conjecture of Ibukiyama. We also prove an integral version of the weight-monodromy conjecture and use it to deduce a level lowering result for cohomological cuspidal automorphic representations of $\operatorname{GSp}_4$.
title A geometric Jacquet-Langlands correspondence for paramodular Siegel threefolds
topic Number Theory
Algebraic Geometry
11G18
url https://arxiv.org/abs/1906.04008