  We elaborate on the extended Hilbert space factorization of Chern Simons
theory and show how this arises naturally from a proper regularization of the
entangling surface in the Euclidean path integral. The regularization amounts
to stretching the entangling surface into a co-dimension one surface which
hosts edge modes of the Chern Simons theory when quantized on a spatial
subregion. The factorized state is a regularized Ishibashi state and reproduces
the well known topological entanglement entropies. We illustrate how the same
factorization arises from the glueing of two spatial subregions via the
entangling product defined by Donnelly and Freidel.
