A variational principle for actions on symmetric symplectic spaces

We present a definition of generating functions of canonical relations, which are real functions on symmetric symplectic spaces, discussing some conditions for the presence of caustics. We show how the actions compose by a neat geometrical formula and are connected to the hamiltonians via a geometrically simple variational principle which determines the classical trajectories, discussing the temporal evolution of such "extended hamiltonians" in terms of Hamilton-Jacobi-type equations. Simplest spaces are treated explicitly. (C) 2003 Elsevier B.V. All rights reserved.