摘要

The averaging principle with a small initial value is constructed for a Hamiltonian perturbed Korteweg-de Vries (KdV) equation under periodic boundary condition @@@ partial derivative(t)u + u(xxx) +6 u u(x) + (del(u)(K-1(u) + cos(n(0)x) K-2(u)))(x) = 0, x is an element of T := R/(2 pi Z) @@@ where the positive integer n(0) is not divisible by three and K-1 and K-2 are real analytic functions. More precisely, any action I with the small initial value parallel to I(0)parallel to((l) over tildes) <= epsilon evolves slowly over a long time interval: @@@ parallel to I(t) - I(0)parallel to((l) over tildes) less than or similar to epsilon, for any vertical bar t vertical bar less than or similar to epsilon(-5/2), @@@ where s is the index of some space.