Property (T) group factors whose Jones index set equals all positive integers
Abstract
Using a m\'elange of techniques at the rich intersection of deformation/rigidity theory, finite index subfactor theory, and geometric group theory, we prove the existence of a continuum of property (T) factors that are pairwise non-stably isomorphic and whose Jones index sets consist of all positive integers. These factors are realized as group von Neumann algebras associated with property (T) generalized wreath-like product groups introduced in [CIOS23b], where is abelian, is a non-parabolic subgroup of a relatively hyperbolic group with residually finite peripheral structure, and is a faithful action with infinite orbits. Integer index subfactors of are constructed from extensions of . This result advances an open question of P. de la Harpe [dlH95].
Keywords
Cite
@article{arxiv.2511.04822,
title = {Property (T) group factors whose Jones index set equals all positive integers},
author = {Ionut Chifan and Junhwi Lim},
journal= {arXiv preprint arXiv:2511.04822},
year = {2025}
}
Comments
22 pages