A multiplicity result for the generalized Kadomtsev-Petviashvili equation

−∞ h(s, y) ds. See [5] for references concerning this equation. A solitary wave is a solution of the form ω(t, x, y) = u(x− ct, y), where c > 0 is fixed. Substituting in (1), we obtain −cux + uxxx + (f(u))x = D−1 x uyy or (−uxx +D−2 x uyy + cu− f(u))x = 0. Existence results have been established by de Bouard and Saut ([3, 4]) for pure power nonlinearities using a minimization method, and by Willem ([10]) for more