Extended KP equations and extended system of KP equations: multiple-soliton solutions

In this work we study an extended Kadomtsev-Petviashvili (KP) equation and a system of KP equations. We show that the extension terms do not kill the integrability of typical models. Hereman's simplified method is used to justify this goal. Multiple soliton solutions will be derived for each model. The analysis highlights the effects of the extension terms on the dispersion relations, and hence on the structures of the solutions. (author)