Paolo Perfetti
A KAM theorem for infinite--dimensional discrete systems
(325K, ps)

ABSTRACT.  Infinite--dimesional, 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