MPEJ Volume 9, No. 1, 15 pp.
Received: Feb 28, 2003. Accepted: Apr 14, 2003.

Paolo Perfetti
A KAM theorem for infinite--dimensional discrete systems

ABSTRACT: Infinite--dimensional, discrete hamiltonian systems of the
type kinetic energy + potential energy over ${\Bbb R}^{{\Bbb Z}}\times
{\Bbb T}^{{\Bbb Z}}$ are studied. The existence of many
quasi--periodic motions with a maximal set of nonzero frequencies is
shown.