In a sequence of celebrated works, Ratner classified invariant ergodic measures and orbit closures of actions of groups generated by unipotent elements on a homogenegous space. Namely, such an orbit closure must be a single orbit by a closed subgroup, and the invariant ergodic measure is the Haar measure on that orbit. In this talk, we go over a special case of Ratner's measure classification theorem when the action group is semisimple. We will follow the exhibition given by Einsiedler.
This week, we will discuss the main proof.
Zoom Info:
https://umich.zoom.us/j/https://umich.zoom.us/j/92258297975 Speaker(s): Thang Nguyen (U Michigan)