(Non) invertibility of C*-extensions

GAP Seminar

Meeting Details

For more information about this meeting, contact Nigel Higson, Ping Xu, Mathieu Stiénon.

Speaker: Jonas Seebach, Aarhus University

Abstract: We briefly review the basics of C*-extensions as defined by Brown, Douglas and Fillmore and generalized by Kasparov. In particular we discuss the notion of invertibility of (equivalence classes of) extensions and quote a couple of wellknown results showing that not all extensions are invertible. We proceed to discuss the notion of asymptotically split extensions due to Thomsen and Manuilov and we demonstrate that in order to obtain a group from the semigroup of all unitary equivalence classes of extensions, it is generally necessary to trivialize the asymptotically split ones. Finally we quote a few recent results in this direction.

Room Reservation Information

Room Number: 106 McAllister

Date: 11/02/2010

Time: 2:30pm - 3:30pm