Deformations of Standard Locally Homogeneous Spaces

Fuente: arXiv
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Main Authors: Kannaka, Kazuki, Kobayashi, Toshiyuki
Format: Preprint
Published: 2025
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author Kannaka, Kazuki
Kobayashi, Toshiyuki
author_facet Kannaka, Kazuki
Kobayashi, Toshiyuki
contents Let $X=G/H$ be a homogeneous space, where $G \supset H$ are reductive Lie groups. We ask: in the setting where $Γ\backslash G/H$ is a standard quotient, to what extent can the discrete subgroup $Γ$ be deformed while preserving the proper discontinuity of the $Γ$-action on $X$? We provide several classification results, including: conditions under which local rigidity holds for compact standard quotients $Γ\backslash X$; criteria for when a standard quotient can be deformed into a nonstandard one; a characterization of the maximal Zariski-closure of discontinuous groups under small deformations; and conditions under which Zariski-dense deformations occur. Proofs of the results stated in this paper are provided in detail in arXiv:2507.03476.
format Preprint
id arxiv_https___arxiv_org_abs_2507_14832
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Deformations of Standard Locally Homogeneous Spaces
Kannaka, Kazuki
Kobayashi, Toshiyuki
Differential Geometry
Primary:57S30, 58H15. Secondary:22D50, 22E40, 22E46, 53C30, 58J50
Let $X=G/H$ be a homogeneous space, where $G \supset H$ are reductive Lie groups. We ask: in the setting where $Γ\backslash G/H$ is a standard quotient, to what extent can the discrete subgroup $Γ$ be deformed while preserving the proper discontinuity of the $Γ$-action on $X$? We provide several classification results, including: conditions under which local rigidity holds for compact standard quotients $Γ\backslash X$; criteria for when a standard quotient can be deformed into a nonstandard one; a characterization of the maximal Zariski-closure of discontinuous groups under small deformations; and conditions under which Zariski-dense deformations occur. Proofs of the results stated in this paper are provided in detail in arXiv:2507.03476.
title Deformations of Standard Locally Homogeneous Spaces
topic Differential Geometry
Primary:57S30, 58H15. Secondary:22D50, 22E40, 22E46, 53C30, 58J50
url https://arxiv.org/abs/2507.14832