We consider Laplacians acting on sections of homogeneous vector bundles over
symmetric spaces. By using an integral representation of the heat semi-group we
find a formal solution for the heat kernel diagonal that gives a generating
function for the whole sequence of heat invariants. We argue that the obtained
formal solution correctly reproduces the exact heat kernel diagonal after a
suitable regularization and analytical continuation.Comment: 29 pages, Proceedings of the 2007 Midwest Geometry Conference in
Honor of Thomas P. Branso