On a decomposition of $p$-adic Coxeter orbits

Fuente: arXiv
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Autor principal: Ivanov, Alexander B.
Formato: Preprint
Publicado: 2021
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author Ivanov, Alexander B.
author_facet Ivanov, Alexander B.
contents We analyze the geometry of some $p$-adic Deligne--Lusztig spaces $X_w(b)$ introduced in [Iva21] attached to an unramified reductive group ${\bf G}$ over a non-archimedean local field. We prove that when ${\bf G}$ is classical, $b$ basic and $w$ Coxeter, $X_w(b)$ decomposes as a disjoint union of translates of a certain integral $p$-adic Deligne--Lusztig space. Along the way we extend some observations of DeBacker and Reeder on rational conjugacy classes of unramified tori to the case of extended pure inner forms, and prove a loop version of Frobenius-twisted Steinberg's cross section.
format Preprint
id arxiv_https___arxiv_org_abs_2109_01424
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle On a decomposition of $p$-adic Coxeter orbits
Ivanov, Alexander B.
Algebraic Geometry
Representation Theory
20G25, 14M15 (primary), 14F20 (secondary)
We analyze the geometry of some $p$-adic Deligne--Lusztig spaces $X_w(b)$ introduced in [Iva21] attached to an unramified reductive group ${\bf G}$ over a non-archimedean local field. We prove that when ${\bf G}$ is classical, $b$ basic and $w$ Coxeter, $X_w(b)$ decomposes as a disjoint union of translates of a certain integral $p$-adic Deligne--Lusztig space. Along the way we extend some observations of DeBacker and Reeder on rational conjugacy classes of unramified tori to the case of extended pure inner forms, and prove a loop version of Frobenius-twisted Steinberg's cross section.
title On a decomposition of $p$-adic Coxeter orbits
topic Algebraic Geometry
Representation Theory
20G25, 14M15 (primary), 14F20 (secondary)
url https://arxiv.org/abs/2109.01424