Closure relations of Newton strata in Iwahori double cosets

2021/06/14 by Stefania Trentin, Trentin, Stefania, Eva Viehmann +1
Mathematics · #Advanced Algebra and Geometry #Algebraic Geometry (math.AG) #Algebraic Geometry and Number Theory #Algebraic structures and combinatorial models #FOS: Mathematics

paper · pdf · doi:10.48550/arxiv.2106.07284

openalex publication_date 2021/06/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We consider the Newton stratification on Iwahori double cosets for a connected reductive group. We prove the existence of Newton strata whose closures cannot be expressed as a union of strata, and show how this is implied by the existence of non-equidimensional affine Deligne-Lusztig varieties. We also give an explicit example for a group of type A₄.

Related

• Minimal Newton strata in Iwahori double cosets
• Generic Newton points and the Newton poset in Iwahori double cosets
• Connectedness of affine Deligne-Lusztig varieties for unramified groups
• On the geometry of the Newton stratification
• Supersingular Kottwitz-Rapoport strata and Deligne-Lusztig varieties