“…Due to the profound theoretical and practical significance, the study of multi-soliton solutions of nonlinear partial differ-ential equations has always been a hot topic. To date, a variety of approaches have been well established to investigate the multi-soliton solutions of nonlinear partial differential equations, such as the inverse scattering method, [9] the Hirota's bilinear method, [10] the Darboux transformation method, [11][12][13] the Riemann-Hilbert approach, [14] the KP hierarchy reduction method, [15][16][17] the generalized unified method, [18,19] and so forth. The Riemann-Hilbert approach as a very powerful approach in dealing with nonlinear partial differential equations with initial-boundary value conditions has attracted more and more attention in recent years.…”