Group actions, groupoids, and their \(C^{*}\)-algebras

Becky Armstrong
University of Sydney
10 July 2017, 3-4pm, Carslaw 375, University of Sydney


\(C^{*}\)-algebras were first introduced in order to model physical observables in quantum mechanics, but are now studied more abstractly in pure mathematics. Much of the current research of \(C^{*}\)-algebraists involves constructing interesting classes of \(C^{*}\)-algebras from various mathematical objects---such as groups, groupoids, and directed graphs---and studying their properties. Groupoid \(C^{*}\)-algebras were introduced by Renault in 1980, and provide a unifying model for \(C^{*}\)-algebras associated to groups, group actions, and graphs. In this talk, I will define topological groupoids and examine Renault's construction of groupoid \(C^{*}\)-algebras. I will discuss several examples of groupoids, including group actions and graph groupoids, and will conclude with a brief description of my PhD research.