Soliton solutions and their degenerations in the (2+1)-dimensional Hirota–Satsuma–Ito equations with time-dependent linear phase speed

This paper focuses on the exact soliton solutions of (2+1)-dimensional generalized Hirota–Satsuma–Ito equations with time-dependent linear phase speed. Based Painlevé integrability test this equation, condition is determined. Then general N-soliton are constructed by Hirota bilinear method. Not only expressions and their degenerations, but also spatial structures presented for different choices parameters, including line soliton, periodic lump interaction forms.