On the flatness of spin local models for split even orthogonal groups

Fuente: arXiv
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Main Author: Yang, Jie
Format: Preprint
Published: 2025
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author Yang, Jie
author_facet Yang, Jie
contents Let $F$ be a complete discretely valued field with ring of integers $\mathcal{O}$ and residue field of characteristic $p>2$. Let $G=\operatorname{GO}_{2n}$ denote the split orthogonal similitude group over $F$. For any parahoric level structure, we prove that the associated spin local model for $G$ is a flat $\mathcal{O}$-scheme with reduced special fiber. This confirms a conjecture of Pappas and Rapoport in the split case. As a corollary, we construct a flat (integral) moduli space of PEL-type D.
format Preprint
id arxiv_https___arxiv_org_abs_2512_16704
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the flatness of spin local models for split even orthogonal groups
Yang, Jie
Number Theory
Let $F$ be a complete discretely valued field with ring of integers $\mathcal{O}$ and residue field of characteristic $p>2$. Let $G=\operatorname{GO}_{2n}$ denote the split orthogonal similitude group over $F$. For any parahoric level structure, we prove that the associated spin local model for $G$ is a flat $\mathcal{O}$-scheme with reduced special fiber. This confirms a conjecture of Pappas and Rapoport in the split case. As a corollary, we construct a flat (integral) moduli space of PEL-type D.
title On the flatness of spin local models for split even orthogonal groups
topic Number Theory
url https://arxiv.org/abs/2512.16704