By using the sine-cosine method proposed recently, we give the exact periodic and soliton solutions of the (2 + 1)-dimensional Bogoyavlenskii equation in this paper. Many new families of exact traveling wave solutions of the (2 + 1)-dimensional Bogoyavlenskii equation are successfully obtained. The computation for the method appears to be easier and faster by general mathematical software.

By using the sine-cosine method proposed recently, we give the exact periodic and soliton solutions of the (2 + 1)-dimensional soliton equation in this paper. Many new families of exact traveling wave solutions of the (2 + 1)-dimensional soliton equation are successfully obtained. The computation for the method appears to be easier and faster by general mathematical software.

We prove that the Schäfer–Wayne short pulse equation (SPE) which describes the propagation of ultra-short optical pulses in nonlinear media is integrable. First, we discover a Lax pair of the SPE which turns out to be of the Wadati–Konno–Ichikawa type. Second, we construct a chain of transformations which relates the SPE with the sine-Gordon equation.

We introduce a nonlocal transformation to generate exact solutions of the constant astigmatism equation zyy + (1/z)xx + 2 = 0. The transformation is related to the special case of the famous Bäcklund transformation of the sine-Gordon equation with the Bäcklund parameter λ = ±1. It is also a nonlocal symmetry.

The quantitative thermodynamic effect of adding a weak, long-range attraction to inverse-power repUlsive potentials is studied. The resulting phase diagrams exhibit two fluid phases and a solid phase. a critical point, a triple point, and, for sufficiently soft repulsions, an additional solid phase with an additional triple point. The effects of attractions other than van der Waals' are studied...

In this paper, the sine-cosine, the standard tanh and the extended tanh methods has been used to obtain solutions of the KadomstevPetviashvili(KP) equation. New solitons solutions and periodic solutions are formally derived. The change of parameters, that will drastically change characteristics of the equation, is examined.

We investigate the classical and nonclassical reductions of the 2+1-dimensional sine-Gordon system of Konopelchenko and Rogers, which is a strong generalisation of the sine-Gordon equation. A family of solutions obtained as a nonclassical reduction involves a decoupled sum of solutions of a generalised, real, pumped Maxwell-Bloch system. This implies the existence of families of solutions, all ...