**Unfortunately the seminar described below has been cancelled as Kai Cieliebak has broken his foot and so is unable to travel to Brussels.** We hope he will be able to visit next semester.

**Note the unusual day!**Kai’s title is

*“String topology and perturbative Chern-Simons theory”*. His abstract is below.

One instance of Chas and Sullivan’s “string topology” is a Lie bialgebra structure on the equivariant loop space homology of a closed oriented manifold. An attempt to construct the underlying chain level structure leads to integrals over configuration spaces closely related to those in perturbative

Chern-Simons theory.After recalling the relevant theories, I will explain the difficulties with this approach due to singular integrands and hidden faces, and how they can be resolved if the manifold is odd dimensional.