Abstract

We prove the existence of almost-periodic solutions for quasi-linear perturbations of the Airy equation. This is the first result about the existence of this type of solutions for a quasi-linear PDE. The solutions turn out to be analytic in time and space. To prove our result we use a Craig–Wayne approach combined with a KAM reducibility scheme and pseudo-differential calculus on mathbb {T}^infty .

Highlights

  • In this paper we study response solutions for almost-periodically forced quasilinear PDEs close to an elliptic fixed point

  • The problem of response solutions for PDEs has been widely studied in many contexts, starting from the papers [24,25], where the Author considers a periodically forced PDE with dissipation

  • In the present paper we study the existence of almost-periodic response solutions, for a quasi-linear PDE on T

Read more

Summary

Introduction

In this paper we study response solutions for almost-periodically forced quasilinear PDEs close to an elliptic fixed point. All the results mentioned above concern semi-linear PDEs and the forcing is quasi-periodic. Concern semi-linear PDEs, with no derivative in the nonlinearity They require a very strong analyticity condition on the forcing term. In the case of a quasi-linear PDE this amounts to study an unbounded non-constant coefficients operator. To deal with this problem, at each step we introduce a change of variables Tn which diagonalizes the highest order terms of the linearized operator. In order to prove the invertibility of the linearized operator after the change of variables Tn is applied, one needs to perform a reducibility scheme: this is done in Sect. For a more detailed description of the technical aspects see Remark 3.2

Functional Setting
The Iterative Scheme
Finally one has n
The Zero-th Step
There is δ0 small enough such that
Elimination of the x-Dependence from the Highest Order Term
Time Dependent Traslation of the Space Variable
Reduction of the First Order Term
Reducibility We now consider an operator L0 of the form
The sets Ek are defined as
Variations
Conclusion of the Proof
A Technical Lemmata
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call