K. Kannaka

collaborators

3 papers

math.DG2026

Hurwitz-Radon numbers and proper actions of semisimple Lie groups

Kazuki Kannaka, Koichi Tojo

We study proper isometric actions of non-compact semisimple Lie groups on pseudo-Riemannian symmetric spaces. Motivated by Okuda's classification of semisimple symmetric spaces adm…

math.DG2025

Zariski-dense deformations of standard discontinuous groups for pseudo-Riemannian homogeneous spaces

Kazuki Kannaka, Toshiyuki Kobayashi

Let $X = G / H$ be a homogeneous space of a Lie group $G$ . When the isotropy subgroup $H$ is non-compact, a discrete subgroup $I^$ may fail to act properly discontinuously on $X$ . In t…

math.DG2025

Zariski dense discontinuous surface groups for reductive symmetric spaces

Kazuki Kannaka, Takayuki Okuda, Koichi Tojo

Let $G / H$ be a homogeneous space of reductive type with non-compact $H$ . The study of deformations of discontinuous groups for $G / H$ was initiated by T.~Kobayashi. In this paper, w…