Based on estimates for the KdV equation in analytic Gevrey classes, a spectral collocation approximation of the KdV equation is proved to converge exponentially fast. Mathematics Subject Classification. 35Q53, 65M12, 65M70. Received: March 31, 2006. Revised: July 11, 2006.

In this paper, we establish exact solutions for a nonlinear evolution equation. The sech method and the exp-function method are used to construct the solitary travelling wave solutions of Lax’s seventh-order KdV equation. These solutions may be important of significance for the explanation of some practical physical problem. Crown Copyright 2008 Published by Elsevier Inc. All rights reserved.

We consider some conditions over the coefficients of the sixth-order KdV equation (KdV6) under which this equation has exact solutions. An algebraic condition for the existence of exact solutions to KdV6 is obtained. A new ansatz is considered to obtain analytic solutions for several forms of it.

An abstract functional framework is developed for the dual Petrov-Galerkin formulation of the initial boundary value problems with a third-order spatial derivative. This framework is then applied to study the wellposedness and decay properties of Airy equation and KdV equation in a finite interval.

We derive the modulation equations or Whitham equations for the Camassa– Holm (CH) equation. We show that the modulation equations are hyperbolic and admit bi-Hamiltonian structure. Furthermore they are connected by a reciprocal transformation to the modulation equations of the first negative flow of the Korteweg de Vries (KdV) equation. The reciprocal transformation is generated by the Casimir...

We generalize the non-linear one-dimensional equation of a fluid layer for any depth and length as an infinite order differential equation for the steady waves. This equation can be written as a q-differential one, with its general solution written as a power series expansion with coefficients satisfying a nonlinear recurrence relation. In the limit of long and shallow water (shallow channels) ...

The Kawahara and modified Kawahara equations are fifth-order KdV type equations and have been derived to model many physical phenomena such as gravitycapillary waves and magneto-sound propagation in plasmas. This paper establishes the local well-posedness of the initial-value problem for Kawahara equation in H(R) with s > − 4 and the local well-posedness for the modified Kawahara equation in H(...

The modulational stability of both the Korteweg-de Vries (KdV) and the Boussinesq wavetralns is investigated using Whltham’s variational method. It is shown that both KdV and Boussinesq wavetrains are modulationally stable. This result seems to confirm why it is possible to transform the KdV equation into a nonlinear Schr’dinger equation with a repulsive potential. A brief discussion of Whltham...

The paper presents two results. First it is shown how the discrete potential modified KdV equation and its Lax pairs in matrix form arise from the Hirota–Miwa equation by a 2-periodic reduction. Then Darboux transformations and binary Darboux transformations are derived for the discrete potential modified KdV equation and it is shown how these may be used to construct exact solutions.