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Bibliographic Details
Main Author:	Bieker, Patrick
Format:	Preprint
Published:	2025
Subjects:	Algebraic Geometry
Online Access:	https://arxiv.org/abs/2508.04876
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author	Bieker, Patrick
author_facet	Bieker, Patrick
contents	We prove a criterion for the normality of Schubert varieties in twisted affine Grassmannians in terms of the order of the algebraic fundamental group of a certain Levi subgroup, in particular in small positive characteristic. As an application, we obtain a similar normality criterion for local models in both equal and mixed characteristic. In particular, we give a classification of normal Pappas-Zhu local models at absolutely special level as well as for adjoint groups of rank 1.
format	Preprint
id	arxiv_https___arxiv_org_abs_2508_04876
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	Normality of Schubert varieties in affine Grassmannians II: The tamely ramified case Bieker, Patrick Algebraic Geometry We prove a criterion for the normality of Schubert varieties in twisted affine Grassmannians in terms of the order of the algebraic fundamental group of a certain Levi subgroup, in particular in small positive characteristic. As an application, we obtain a similar normality criterion for local models in both equal and mixed characteristic. In particular, we give a classification of normal Pappas-Zhu local models at absolutely special level as well as for adjoint groups of rank 1.
title	Normality of Schubert varieties in affine Grassmannians II: The tamely ramified case
topic	Algebraic Geometry
url	https://arxiv.org/abs/2508.04876

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