In this paper, we study the generalized coupled Hirota–Satsuma KdV system by using the two new improved projective Riccati equations method. As a result, many explicit exact solutions, which contain new solitary wave solutions, periodic wave solutions and combined formal solitary wave solutions and combined formal periodic wave solutions are obtained. c © 2007 Published by Elsevier Ltd

The purpose of this paper is to give explicit constructions unitary $t$-designs in the group $U(d)$ for all $t$ and $d$. It seems that were so far known only very special cases. Here construction means entries matrices are given by values elementary functions at root some polynomials. We will discuss what best such $4$-designs $U(4)$ obtained these methods. Indeed we an inductive designs on com...

Liu [Liu Rui, Coexistence of multifarious exact nonlinear wave solutions for generalized b-equation, Inter. J. Bifurcation and Chaos, 20, pp. 3193-3208, 2010] investigated the coexistence of multifarious exact traveling wave solutions of the generalized b-equation, and also presented three conjectures and two questions. In this note, by using the method of complete discrimination system for pol...

Kudryashov in [ Phys. Lett. A 342 (2005) 99-106] used simplest nonlinear differential equations like the Riccati equation, the equation for the Jacobi elliptic function to present a new approach for searching exact solutions of nonlinear partial differential equations. As application, he obtained a kind of exact solutions to the Fisher equation. In this letter, more explicit exact solitary wave...

By using the bifurcation theory of dynamical systems to study the dynamical behavior of the Green–Naghdi equations, the existence of solitary wave solutions along with smooth periodic traveling wave solutions is obtained. Under different regions of parametric spaces, various sufficient conditions to guarantee the existence of the above solutions are given. Some exact and explicit parametric rep...

Q -conditional symmetries of the classical diffusive Lotka–Volterra system in the case of one space variable are completely described and a set of such symmetries in explicit form is constructed. The relevant non-Lie ansatz to reduce the diffusive Lotka–Volterra systems with correctly specified coefficients to ODE systems and examples of new exact solutions are found. A possible biological inte...

In this paper, by considering the variational iteration method, a kind of explicit exact and numerical solutions to the Lienard equation is obtained, and the numerical solutions has been compared with their known theoretical solution. The variational iteration method is based on Lagrange multipliers for identification of optimal value of parameters in a functional. Using this method, it is poss...

This paper proposes robust algorithms to perform deconvolution and inversion of the heat equation starting from 1D and 2D discrete noised data. The solutions are provided as splines that minimize some parameterized quadratic functionals. Parameters choice determines the trade-off between the regularity of the solution and the approximation of the initial data. The solutions are derived in an ex...