EVENT DETAILS AND ABSTRACT

Title: Inertia Groupoids and their singularity structure or why we need a concept of stratified groupoids
Speaker: Markus Pflaum
Speaker Info: University of Colorado - Boulder
Brief Description:
Special Note:
Abstract:

The inertia space of a compact Lie group action or more generally of a proper Lie groupoid has an interesting singularity structure. Unlike the quotient space of the group action, respectively the groupoid, the inertia space can not be stratified by orbit types, in general. In the talk we explain this phenomenon. Moreover, we show that that leads naturally to the concept of a stratified groupoid which lies in between the one of a Lie groupoid and the one of a topological groupoid. Finally we show that a de Rham theorem holds for inertia spaces and indicate a connection between the inertia space and the non-commutative geometry of the underlying groupoid in terms of basic relative Grauert-Grothendieck forms on the inertia space.