On orthogonal systems, two-sided bases and regular subfactors

27 Jul 2020 · Bakshi Keshab Chandra, Gupta Ved Prakash ·

We prove that a regular subfator of type $II_1$ with finite Jones index always admits a two-sided Pimsner-Popa basis. This is preceeded by a pragmatic revisit of Popa's notion of orthogonal systems.