Higher Kazhdan projections and delocalised $\ell^ 2$-Betti numbers
Operator Algebras
2026-05-27 v2 Group Theory
K-Theory and Homology
Abstract
We provide an explicit description of the K-classes of higher Kazhdan projections in degrees greater than 0 for specific free product groups and Cartesian product groups. Employing this description, we obtain new calculations of Lott's delocalised -Betti numbers. Notably, we establish the first non-vanishing results for infinite groups.
Keywords
Cite
@article{arxiv.2405.03837,
title = {Higher Kazhdan projections and delocalised $\ell^ 2$-Betti numbers},
author = {Sanaz Pooya and Hang Wang},
journal= {arXiv preprint arXiv:2405.03837},
year = {2026}
}
Comments
19 pages, Accepted for publication in the Annals of K-theory