Invariant manifolds of maps and vector fields with nilpotent parabolic tori

Abstract

We consider analytic maps and vector fields defined in R2×Td, having a d-dimensional invariant torus T. The map (resp. vector field) restricted to T defines a rotation of Diophantine frequency vector ω∈Rd, and its derivative restricted to transversal directions to T does not diagonalize. In this context, we give conditions on the coefficients of the nonlinear terms of the map (resp. vector field) under which T possesses stable and unstable invariant manifolds, and we show that such invariant manifolds are analyitic away from the invariant torus. We also provide effective algorithms to compute approximations of parameterizations of the invariant manifolds, and a posteriori theorems that can be used to validate numerical computations. Moreover, we present some applications of the results.