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arXiv · 2102.09870

Monodromy and Irreducibility of Igusa Varieties

Pol van Hoften·Luciena Xiao Xiao
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Abstract

We determine the irreducible components of Igusa varieties for Shimura varieties of Hodge type under a mild condition and use that to compute the irreducible components of central leaves. In particular, we show that a strong version of the discrete Hecke orbit conjecture is false in general. Our method combines recent work of D'Addezio on monodromy groups of compatible local systems with a generalisation of a method of Hida, using the Honda--Tate theory for Shimura varieties of Hodge type developed by Kisin--Madapusi--Shin. We also determine the irreducible components of Newton strata in Shimura varieties of Hodge type by combining our methods with recent work of Zhou--Zhu.

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Pol van Hoften, Luciena Xiao Xiao. 2021-02-19. Monodromy and Irreducibility of Igusa Varieties. https://doi.org/10.1353/ajm.2025.a954646

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