CANCELLED Just infinite C*-algebras (Mikael Rørdam, Copenhagen)

21.04.2016 16:15

There is a well-established notion of just infinite groups, i.e., infinite groups for which all proper quotients are finite. The residually finite just infinite groups are particularly interesting. They are either branch groups (for example Grigorchuk's group of intermediate growth) or hereditarily just infinite groups (for example Z, the infinite dihedral group, and SL_n(Z)). It is natural to consider the analogous notion for C*-algebras, whereby a C*-algebra is just infinite if it is infinite dimensional and all its proper quotients are finite dimensional. The study of these C*-algebras was motivated by the question when a group C*-algebra of a just infinite group has this property. We give a classification of just infinite C*-algebras in terms of their primitive ideal space. We describe examples and properties of residually finite dimensional just infinite C*-algebras; and we will discuss when group C*-algebras can be just infinite. This is joint work with R. Grigorchuk and M. Musat.

The colloquium will be followed by an appetizer

Lieu

Room 17, Colloque

entrée libre