Groups and Operator Algebras Seminar

Speaker: Soham Chakraborty (ENS Paris)

Title: The existence and uniqueness problem for trace scaling flows on semifinite factors. 

Abstract: Since the breakthrough work of Connes on the classification of injective factors, the existence and uniqueness of continuous trace scaling flows on a given II_\infty factor has remained a challenging problem in general. Haagerup's seminal work showed that the unique injective II_\infty factor has a unique such flow. Subsequently, Radulescu showed the existence of such a flow on L(F_\infty) \otimes B(H) (its uniqueness is still open), and Dykema showed that the existence of such a flow on L(F_2) \otimes B(H) implies that all free group factors are isomorphic. In this talk we shall see how some Lie algebraic techniques can be used to compute the number of 'distinct' trace scaling flows on full II_\infty factors whose outer automorphism groups are locally compact. This talk is based on joint work with Sergiu Novac.