Near-invariant tori on exponentially long time for Poisson systems

This paper deals with the near-invariant tori for Poisson systems. It is shown that the orbits with the initial points near the Diophantine torus approach some quasi-periodic orbits over an extremely long time. In particular, the results hold for the classical Hamiltonian system, and in this case the drift of the motions is smaller than the one in the past works. © 2006 Elsevier Inc. All rights reserved.