Hans Koch
A Renormalization Group for Hamiltonians, with Applications to KAM Tori
(163K, plain TeX)

ABSTRACT.  We describe a family of renormalization group transformations
which apply to the problem of stability of invariant tori
for analytic Hamiltonians.
Each of these transformations corresponds to a fixed rotation vector,
within a certain class of vectors in R^d.
As an application, we prove a KAM-type theorem that yields
analytic invariant d-tori depending analytically on the Hamiltonian.