# Meeting Details

Title: The Yamabe number is a spin-bordism invariant Center for Dynamics and Geometry Seminars Bernd Ammann, University of Regensburg If M is a compact manifold, then the conformal Yamabe invariant of $(M,[g_0])$ is defined as the infimum of the Einstein-Hilbert functinal over all volume-1-metrics in a given conformal class [g_0]. Taking the supremum over all conformal classes we obtain the Yamabe number of M. It is positive iff M admits a metric of positive scalar curvature. We show that this number is almost monotone under surgeries of codimension \geq 3, and it follows that in a certain range of values, it is a new type of spin-bordism invariant.