Hall 123

Commuting squares and angle between intermediate subfactors.

Keshab Bakshi

IMSc, Chennai

In this talk we will focus on subfactors of type $II_1$ factors. In the theory of subfactors the so-called 'commuting squares' becomes a very useful tool. We introduce a natural notion of 'angle' between intermediate subfactors and investigate relationship with commuting squares. More precisely, using 'angle' we characterize commuting squares into various equivalent conditions. This we do after expressing 'angle' in terms of 'Pimsner-Popa basis'. This is a part of a recent joint work with Zhengwei Liu, Sayan Das and Yunxiang Ren.