Non-geometric property (T) of warped cones
Group Theory
2025-07-31 v3 Dynamical Systems
Operator Algebras
Abstract
In this paper, we study the geometric property (T) for discretized warped cones of an action on a compact Lie group by its finitely generated subgroup. We show that if a subgroup is dense in , then the associated discretized warped cone does not have geometric property (T) for any sequence of positive numbers converging to . This result applies to certain ergodic actions of groups with property (T), for example, the action of on with . As an application, we obtain new examples of expanders without geometric property (T), including certain superexpanders.
Cite
@article{arxiv.2503.04578,
title = {Non-geometric property (T) of warped cones},
author = {Jintao Deng and Ryo Toyota},
journal= {arXiv preprint arXiv:2503.04578},
year = {2025}
}