  A Chern-Simons action written with Christoffel Symbols has a natural gauge
symmetry of diffeomorphisms. This Chern-Simons action will induce a
Wess-Zumio-Witten model on the boundary of the manifold. If we restrict the
diffeomorphisms to chiral diffeomorphism, the Wess-Zumio-Witten model is
equivalent to a quantum Liouville action.
