"Geometry and Analysis on Groups" Research Seminar
Exotic group \(C^*\)-algebras from representation theory.
Martin Finn-Sell (Vienna)
I will summarise the results of a paper of Brown-Guentner, which defines new \(C^*\)-completions of discrete groups beyond the regular and maximal ones. I will also explain the relationship between analytic properties of discrete groups, such as property (T) and the Haagerup property, and certain \(C^*\)-completions - these results are reminiscent of the Hulanicki-Reiter characterisation of amenability in terms of \(C^*\)-completions.