Automorphic congruences and torsion in the cohomology of a simple unitary Shimura variety

Pascal Boyer

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arXiv · 1610.10020

Automorphic congruences and torsion in the cohomology of a simple unitary Shimura variety

Pascal Boyer

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Abstract

We first give a relative flexible process to construct torsion cohomology classes for Shimura varieties of Kottwitz-Harris-Taylor type with coefficient in a non too regular local system. We then prove that associated to each torsion cohomology class, there exists a infinity of irreducible automorphic representations in characteristic zero, which are pairwise non isomorphic and weakly congruent.

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Pascal Boyer. 2016-10-31. Automorphic congruences and torsion in the cohomology of a simple unitary Shimura variety. https://arxiv.org/abs/1610.10020

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