Xg. Geng et Wx. Ma, A GENERALIZED KAUP-NEWELL SPECTRAL PROBLEM, SOLITON-EQUATIONS AND FINITE-DIMENSIONAL INTEGRABLE SYSTEMS, Nuovo cimento della Società Italiana di Fisica. A. Nuclei, particles and fields, 108(4), 1995, pp. 477-486
A generalized Kaup-Newell spectral problem is introduced. This spectra
l problem corresponds to infinitely many hierarchies of soliton equati
ons. Further two reductions of the generalized Kaup-Newell spectral pr
oblem are discussed and two new hierarchies of associated soliton equa
tions are derived. Through non-linearization of two reductive spectral
problems, two new finite-dimensional integrable systems are engendere
d, which possess non-confocal involutive integrals of motion.