Operator algebra seminar

Speaker: Hiroshi Ando, University of Copenhagen

Title: On the noncommutativity of the central sequence algebra F(A)

Abstract: We show that the central sequence C*-algebra of the free group C*(F_n) (n≥2) is noncommutative, answering a question of Kirchberg in 2004. This is in contrast to the fact that the W*-central sequence algebra of the group von Neumann algebra L(F_n) is trivial. The idea of the proof is to find a surjection from a (subalgebra of) the central sequence algebra onto the W*-central sequence algebra, which was first proved by Sato and later generalized by Kirchberg-Rørdam in tracial setting.

This is joint work with Eberhard Kirchberg.