A character approach to the ISR property
Abstract
We develop a character approach to study the invariant von Neumann subalgebras rigidity property (abbreviated as the ISR property) introduced in Amrutam-Jiang's work. First, we introduce the non-factorizable regular character property for groups and show that this implies the ISR property for any infinite ICC groups with trivial amenable radical.Various examples are shown to have this property. Second, we apply known classification results on indecomposable characters to show approximately finite groups have the ISR property. Based on this approach, we also construct non-amenable groups with the ISR property while having non-trivial amenable radical or without the non-factorizable regular character property.
Cite
@article{arxiv.2410.14517,
title = {A character approach to the ISR property},
author = {Artem Dudko and Yongle Jiang},
journal= {arXiv preprint arXiv:2410.14517},
year = {2025}
}
Comments
v2. typos and imprecise statements corrected and proof of Theorem 4.5 is simplified. Main theorems unchanged. Preliminary version. Comments are welcome