Singularities of local models

Fuente: arXiv
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Main Authors: Fakhruddin, Najmuddin, Haines, Thomas, Lourenço, João, Richarz, Timo
Format: Preprint
Published: 2022
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author Fakhruddin, Najmuddin
Haines, Thomas
Lourenço, João
Richarz, Timo
author_facet Fakhruddin, Najmuddin
Haines, Thomas
Lourenço, João
Richarz, Timo
contents We construct local models of Shimura varieties and investigate their singularities, with special emphasis on wildly ramified cases. More precisely, with the exception of odd unitary groups in residue characteristic $2$ we construct local models, show reducedness of their special fiber, Cohen$-$Macaulayness and in equi-characteristic also (pseudo-)rationality. In mixed characteristic we conjecture their (pseudo-)rationality. This is based on the construction of parahoric group schemes over two-dimensional bases for wildly ramified groups and an analysis of singularities of the attached Schubert varieties in positive characteristic using perfect geometry.
format Preprint
id arxiv_https___arxiv_org_abs_2208_12072
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Singularities of local models
Fakhruddin, Najmuddin
Haines, Thomas
Lourenço, João
Richarz, Timo
Algebraic Geometry
Number Theory
We construct local models of Shimura varieties and investigate their singularities, with special emphasis on wildly ramified cases. More precisely, with the exception of odd unitary groups in residue characteristic $2$ we construct local models, show reducedness of their special fiber, Cohen$-$Macaulayness and in equi-characteristic also (pseudo-)rationality. In mixed characteristic we conjecture their (pseudo-)rationality. This is based on the construction of parahoric group schemes over two-dimensional bases for wildly ramified groups and an analysis of singularities of the attached Schubert varieties in positive characteristic using perfect geometry.
title Singularities of local models
topic Algebraic Geometry
Number Theory
url https://arxiv.org/abs/2208.12072