04-27【Jikang Wang】Ricci limit spaces are semi-locally simply connected

Time:2023-03-28Views:28

Speaker: Jikang Wang(Fields Institute, Canada)

Time: 09:00-10:00, Apr 27, 2023

Room: Room 1124, Material Science Research Building (Section C)


   

In this talk, we will discuss local topology of a Ricci limit space $(X,p)$, which is the pointed Gromov-Hausdorff limit of a sequence of complete $n$-manifolds with a uniform Ricci curvature lower bound. I will show that $(X,p)$ is semi-locally simply connected, that is, for any point $x \in X$, we can find a small ball $B_r(x)$ such that any loop in $B_r(x)$ is contractible in $X$. More generally, we can prove that any RCD* spaces are semi-locally simply connected. We will also discuss some applications and questions. Partial of this material is joint work with Jiayin Pan.