Degenerating products of flag varieties and applications to the Breuil–Mézard conjecture

Bartlett, R. (2024) Degenerating products of flag varieties and applications to the Breuil–Mézard conjecture. Selecta Mathematica, 30, 17. (doi: 10.1007/s00029-023-00905-3)

Abstract

We consider closed subschemes in the affine grassmannian obtained by degenerating e-fold products of flag varieties, embedded via a tuple of dominant cocharacters. For G=GL2, and cocharacters small relative to the characteristic, we relate the cycles of these degenerations to the representation theory of G. We then show that these degenerations smoothly model the geometry of (the special fibre of) low weight crystalline subspaces inside the Emerton–Gee stack classifying p-adic representations of the Galois group of a finite extension of Qp. As an application we prove new cases of the Breuil–Mézard conjecture in dimension two.

• Item Type: Articles
• Additional Information: The project was funded by the Deutsche Forschungsgemainschaft (DFG, German Research Foundation)-Project ID 427320536-SFB1442, as well as under Germany's Excellence Strategy EXC2044390685587, Mathematics Munster: Dynamics-Geometry-Structure.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Bartlett, Dr Robin
• Authors: Bartlett, R.
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Mathematics
• Journal Name: Selecta Mathematica
• Publisher: Springer
• ISSN: 1022-1824
• ISSN (Online): 1420-9020
• Copyright Holders: Copyright © Crown 2024
• Publisher Policy: Reproduced under a Creative Commons licence