PSU Mark
Eberly College of Science Mathematics Department

Meeting Details

For more information about this meeting, contact Nigel Higson, John Roe, Ping Xu, Mathieu Stienon.

Title:A new example of a 'natural' C*-algebra for which Ext is not a group
Seminar:Noncommutative Geometry Seminar
Speaker:Jonas Seebach, Aarhus University
We recall a sufficient condition for a separable C*-algebra to have non-invertible extensions (by the compact operators on a separable infinite-dimensional Hilbert space). We then outline a proof of the fact that the reduced group C*-algebra of a socalled torus knot group has non-invertible extensions. The proof relies on a deep result by Haagerup and Thorbjørnsen but is otherwise relatively elementary.

Room Reservation Information

Room Number:MB106
Date:11 / 04 / 2010
Time:02:30pm - 03:30pm