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arXiv · 2609.19860

A Comparison Theorem for Parahoric Character Sheaves

Zhihang Yu
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Abstract

We establish a Jordan decomposition formula for the characteristic functions of the character sheaves on parahoric subgroups defined in \cite{INY25}. For a sufficiently large $q$, these functions are $(-1)^{\dim G}$ times the corresponding deep level Deligne--Lusztig characters, extending \cite{Lu90} to positive depth. We also prove the orthogonality for the generalized deep level Green functions and the character sheaves functions. As an application, we present a sheaf-theoretic expression to the multiplicity of the $G^{F^2}$ character restricted to $G^{F}$.

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Zhihang Yu. 2026-09-17. A Comparison Theorem for Parahoric Character Sheaves. https://arxiv.org/abs/2609.19860

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