06.11.2024, 14:00 - 16:00
– Campus Golm, Building 9, Room 2.22 and via Zoom
Institutskolloquium
Graphon Models for Inhomogeneous Random Graphs
Olga Klopp (Paris), Nicolas Verzelen (Montpellier)
Steven Rosenberg (Boston University)
It is difficult to say much about the topology of the diffeomorphism group and isometry group of a closed manifold, and few high dimensional results are known. In work with Staoshi Egi and Yoshi Maeda, we prove that circle bundles N over 4k-dimensional symplectic manifolds have infinite \pi_1(Diff(N)) and \pi_1(Isom(N)). The infinite order element in these fundamental groups is detected by a Chern-Simons-type class on the loop space LN built from the Wodzicki residue. This class is calculated by examining some natural Riemannian metrics on LN.