Wayne C.E., Pillet C.-A.
Invariant manifolds for a class of dispersive,
Hamiltonian, partial differential equations
(145K, postscript)

ABSTRACT.  We construct an invariant manifold of periodic orbits for a class of
non-linear Schr\"odinger equations. Using standard ideas of the theory of
center manifolds, we rederive the results of Soffer and Weinstein on the
large time asymptotics of small solutions (scattering theory).