摘要

Starting from a generalized Kaup-Newell spectral problem involving an arbitrary function, we derive a hierarchy of nonlinear evolution equations, which is explicitly related to many important equations such as Kaup-Newell equation, Chen-Lee-Liu. equation, Gerdjikov-Ivanov equation, Burgers equation, modified Korteweg-de Vries equation and Sharma-Tasso-Olever equation. It is also shown that the hierarchy is integrable in Lionville's sense and possesses multi-Hamiltonian structure.