Seminar| Institute of Mathematical Sciences
Time：Wednesday, March 8th, 2023, 15:00-16:00
Location：RS408, IMS
Speaker: Yuhang Liu, Xi-an Jiaotong Liverpool university
Abstract: This talk will be a survey talk presenting the interplay between group actions and positive curvature. I will first briefly go through smooth Lie group actions on compact manifolds, including the notions of orbit types and orbit spaces as well as the smooth slice theorem. Next we will move on to the special case of group actions on closed Riemannian manifolds with positive sectional curvature. We will talk about Alexandrov spaces with positive curvature and the extent lemma. If time permits, we will sketch the proof of Hsiang-Kleiner's theorem concerning circle actions on positively curved 4-manifolds.