Stickiness of KAM tori for higher dimensional beam equation

Abstract

This paper is concerned with the stickiness of invariant tori obtained by KAM technics (so-called KAM tori) for higher dimensional beam equation. We prove that the KAM tori are sticky, i.e. the solutions starting in the $\delta$-neighborhood of KAM torus still stay close to the KAM torus for a polynomial long time such as $|t|\leq \delta^{-\mathcal{M}}$ with any $\mathcal{M}\geq 0$, by constructing a partial normal form of higher order, which satisfies $p$-tame property, around the KAM torus.