06.11.2024, 14:00 - 16:00
– Campus Golm, Building 9, Room 2.22 and via Zoom
Institutskolloquium
Graphon Models for Inhomogeneous Random Graphs
Olga Klopp (Paris), Nicolas Verzelen (Montpellier)
Jonathan Taylor (UP)
Renault's theorem for Cartan pairs of C*-algebras states that C*-algebras with particularly nice commutative subalgebras, called Cartan subalgebras, admit twisted groupoid models. One of the conditions that Renault required of a Cartan subalgebra was that there is a conditional expectation projecting from the ambient C*-algebra down to the subalgebra. In the groupoid setting, this corresponds to restricting functions on the groupoid to the unit space of the groupoid. In my PhD thesis, I showed that this condition can be relaxed, to allow for algebras that do not project nicely down to the subalgebra, but have conditional expectations taking values in a slightly larger algebra. Such inclusions still have twisted groupoid models, but the groupoids are no longer Hausdorff.