摘要
This paper is concerned with the derivative nonlinear Schr?dinger equation with periodic boundary conditions.We obtain complete Birkhoff normal form of order six.As an application,the long time stability for solutions of small amplitude is proved.
基金
Supported by NNSFC(Grant Nos.11671280,11822108)
Fok Ying Tong Education Foundation(Grant No.161002)。
