Graduate School of Mathematical Sciences, The University of Tokyo
Journal of Mathematical Sciences, The University of Tokyo. Vol. 3 (1996), No. 1, Page 57-72
The symbol of the fundamental solution for a degenerate parabolic pseudo-differential operator of order $m\,(>0)$ can be described in terms of a Hamiltonian path integral. This Hamiltonian path integral converges in the topology of the symbol class $\Sn$ and in the weak topology of the symbol class $\So$.