Abstract: Given a group G one classically studies all its linear representations, that is homomorphisms from the abstract (or topological) group G to an algebraic group H. Along with H we attach the category of algebraic varieties on which it acts. Along with G, the category of measurable actions. A representation from G to H links these two categories. It is natural to extend the notion of a group representation to a representation of an action (or a groupoid). This point of view appears to be quite fruitful. In my talk I will explain the basic ideas and some of the applications, without assuming prior knowledge neither in Algebraic Geometry nor in Ergodic Theory.The talk is based on a joint work with Alex Furman.

Coffee will be served at 12:00 before the lecture
at Schreiber building 006