# Perturbations of the defocusing nonlinear Schrödinger equation

Grébert, B; Kappeler, T (2003). Perturbations of the defocusing nonlinear Schrödinger equation. Milan Journal of Mathematics, 71:141-174.

## Abstract

We prove that many finite dimensional tori, invariant under the flow of the defocusing nonlinear Schrödinger equation, persist under small Hamiltonian perturbations.These invariant tori are not necessarily close to the zero solution.

We prove that many finite dimensional tori, invariant under the flow of the defocusing nonlinear Schrödinger equation, persist under small Hamiltonian perturbations.These invariant tori are not necessarily close to the zero solution.