We present a general result of transverse nonlinear instability of 1-d solitary waves for Hamiltonian PDE’s for both periodic or localized transverse perturbations. Our main structural assumption is that the linear part of the 1d model and the transverse perturbation “have the same sign”. Our result applies to the generalized KP-I equation, the Nonlinear Schrödinger equation, the generalized Bo...

In this paper, the variational iteration method (VIM) is reintroduced with Laplace transforms and the Padé technique treatment to obtain closed form solutions of nonlinear equations. Some examples, including the coupled Burger’s equation, compacton k(n, n) equation, Zakharov–Kuznetsov Zk(n, n) equation, and KdV and mKdV equations are given to show the effectiveness of the coupled VIM–Laplace–Pa...

Our motivation is the following problem: to describe all positive solutions of a semilinear elliptic equation Lu = uα with α > 1 in a bounded smooth domain E ⊂ Rd. In 1998 Dynkin and Kuznetsov solved this problem for a class of solutions which they called σ-moderate. The question if all solutions belong to this class remained open. In 2002 Mselati proved that this is true for the equation ∆u = ...

In this paper, a new fractional sub-equation method is proposed for finding exact solutions of fractional partial differential equations (FPDEs) in the sense of modified Riemann-Liouville derivative. With the aid of symbolic computation, we choose the space-time fractional Zakharov-Kuznetsov-Benjamin-Bona-Mahony (ZKBBM) equation in mathematical physics with a source to illustrate the validity a...

While in theGraduate School at theLeningradUniversity,Vadimcameunder the influence of Professor Igor V. Komarov who instilled in him a lasting interest in the phenomenonof integrability in classical andquantummechanics.Vadim’s firstwork (Komarov & Kuznetsov 1987) gave voice to his remarkable creativity in finding a new explicit formula for the angle variables in the Kowalevski top. Following th...