Douglas Lectures

Date: April 4, 2019

Time: 4:00PM - 5:00PM

Location: Blocker 117

Speaker: Vaughan Jones, Vanderbilt University

Title: What we know and do not know about subfactors

Abstract: Haagerup discovered the "first" subfactor whose index is bigger than 4-the index is $\frac{5+\sqrt {13}}{2}$. Inspired by Haagerup a group of people tried to extend the classification of subfactors as far beyond index 4 as possible. The current record is 5.25 but the effort has stalled to a certain extent because of a proliferation of potential principal graphs. I will describe the classification and some of the methods used in it. In fact there are other subfactors which fall outside the scope of the classification program which remain totally mysterious.