25 April 2014, 13:30–15:00
Fields institute, Room 210
Speaker: Alessandro Vignati.
Title: An algebra whose subalgebras are characterized by density.
Abstract: A long-standing open problem is whether or not every amenable operator algebra is isomorphic to a C*-algebra. In a recent paper, Y. Choi, I. Farah and N. Ozawa provided a non separable counterexample. After an introduction, building on their work and using the full power of a Luzin gap, we provide an example of an amenable operator algebra A such that every amenable nonseparable subalgebra of A is not isomorphic to a C*-algebra, while some “reasonable” separable subalgebras are. In the end we describe some interesting property of the constructed object related to the Kadison-Kastler metric.