On the moduli description of ramified unitary local models of signature $(n-1,1)$

Fuente: arXiv
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Main Author: Luo, Yu
Format: Preprint
Published: 2024
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_version_ 1866913833081110528
author Luo, Yu
author_facet Luo, Yu
contents We provide a moduli description of the ramified unitary local model of signature $(n-1,1)$ with arbitrary parahoric level structure, assuming the residue field has characteristic not equal to $2$, thereby confirming a conjecture of Smithling. Our approach involves writing down explicit equations for the special fiber and proving that they define a normal, Cohen-Macaulay scheme, which is also of independent interest. As applications, we obtain moduli descriptions for: (1) ramified unitary Pappas-Zhu local models with arbitrary parahoric level; (2) the irreducible components of their special fiber in the maximal parahoric case; (3) integral models of ramified unitary Shimura varieties with arbitrary (quasi-)parahoric level.
format Preprint
id arxiv_https___arxiv_org_abs_2404_10723
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the moduli description of ramified unitary local models of signature $(n-1,1)$
Luo, Yu
Algebraic Geometry
Number Theory
We provide a moduli description of the ramified unitary local model of signature $(n-1,1)$ with arbitrary parahoric level structure, assuming the residue field has characteristic not equal to $2$, thereby confirming a conjecture of Smithling. Our approach involves writing down explicit equations for the special fiber and proving that they define a normal, Cohen-Macaulay scheme, which is also of independent interest. As applications, we obtain moduli descriptions for: (1) ramified unitary Pappas-Zhu local models with arbitrary parahoric level; (2) the irreducible components of their special fiber in the maximal parahoric case; (3) integral models of ramified unitary Shimura varieties with arbitrary (quasi-)parahoric level.
title On the moduli description of ramified unitary local models of signature $(n-1,1)$
topic Algebraic Geometry
Number Theory
url https://arxiv.org/abs/2404.10723