Since the heat kernel of the sub-Laplacian on Heisenberg group was constructed in an explicit integral form by A. Hulanicki, we have several ways to construct the heat kernel for the sub-Laplacian and the Laplacian on 2-step nilpotent Lie groups. In this course we explain a method effectively employed by Beals-Gaveau-Greiner, so called the complex Hamilton-Jacobi theory, and illustrate the construction of the heat kernel for general 2-step cases. Main contents of the course will be the discussion on the solution of the generalized Hamilton-Jacobi equation and a quantity similar to van Vleck determinant and their roles in the integral expression of the heat kernel. We expect this method will work also for 3-step cases to construct the heat kernel together with the theory of elliptic functions. So as an example, we consider the solution of the generalized Hamilton-Jacobi equation for the lowest dimensional 3-step nilpotent Lie group (Engel group). If we have an enough time, we discuss a hierarchy of heat kernels for the three dimensional Heisenberg group and Heisenberg manifolds as a simple example.
○評価方法
出席状況(60%)、レポート(40%)
○参考書
Kenro Furutani : Heat Kernels of the sub-Laplacian and the Laplacian on Nilpotent Lie Groups /最初の講義で配ります。 R. Beals, B. Gaveau and P. Greiner "The Green Function of Model Step two Hypoelliptic Operators and the Analysis of Certain Tangential Cauchy Riemann Complexes, Advances in Mathematics Vol.121(1996), 288--345." Academic press 1996年 Volume 121