Figure 3

(a1), (b1) Overtaking elastic interactions of dark four-soliton solution \(\widetilde{u}_{n}\) in (45) with the parameters \(r_{1}=1\), \(r_{2}=-1\), \(r_{3}=\frac{1}{2}\), \(r_{2}=-\frac{1}{2}\), \(\lambda_{1}=-4\), \(\lambda_{2}=-3\), \(\lambda_{3}=-2.5\), \(\lambda_{4}=-2\). (a2), (b2) Overtaking elastic interactions of bright four-soliton solution \(\widetilde{v}_{n}\) in (45) with the same parameters as in (a1), (b1). The interaction processes for (c1) \(\widetilde{u}_{n}\) and (c2) \(\widetilde{v}_{n}\) at \(t=-20\) (dash-dot line), \(t=0\) (dashed line), and \(t=20\) (solid line)