April 30, 2021
Title: Proper groupoids and Riemannian geometry
Speaker: Mateus de Melo
In this talk, we will explore relationships between Riemannian geometry and Lie groupoids. We will begin by reviewing the correspondence between effective proper isometric actions and closed subgroups of the isometry group, then we will see how to translate it to Lie groupoids. Next, we discuss the linear holonomy groupoid for singular Riemannian foliations and show that its closure is a proper Lie groupoid. We finish by giving results about how far a Riemannian groupoid is from being proper. This talk is based on joint work with Marcos Alexandrino, Marcelo Inagaki, and Ivan Struchiner.