“…It is known that there have been several systematic methods to obtain the finite genus solutions of soliton equations such as algebro-geometric method, the inverse scattering transformation for periodic problem, the nonlinearization approach and others [11,27,5,7,33,28,16,29,6,19,21,3]. These methods have been widely used to solve soliton equations associated with the 2 × 2 matrix spectral problems, by which finite genus solutions to a great deal of integrable models have been successfully constructed, for example, the KdV [11,27,5,7], the discrete AblowitzLadik [33,28,16], the AKNS [19,21], and the Toda lattice equations [7], etc.…”