Painlevé analysis and new analytic solutions for variable-coefficient Kadomtsev-Petviashvili equation with symbolic computation

The variable-coefficient Kadomtsev-Petviashvili (KP) equation is hereby under investigation. Painlevé analysis is given out, and an auto-Bäcklund transformation is presented via the truncated Painlevé expansion. Based on the auto-Bäcklund transformation, new analytic solutions are given, including the soliton-like and periodic solutions. It is also reduced to a (1+1)-dimensional partial differential equation via classical Lie group method and the Painlevé I equation by CK direct method.     

Auto-Bäcklund transformation and similarity reductions for coupled Burger’s equation

In this work, we applied Bäcklund transformation and similarity reduction for coupled Burger’s equation. Clarkson and Kruskal developed a direct and simple method to obtain more similarity solutions of nonlinear partial differential equation. We received our inspiration from Fan’s article, as far as we think that our work is an extended one from the Fan’s has done in his paper. As a result of this study, we obtained solitary wave solutions and traveling wave solutions of coupled Burger’s equation.     

The Kinematics of the Planar Motion of Ideal Fiber-Reinforced Fluids: An Integrable Reduction and Bäcklund Transformation

We establish that the kinematic constraints on the steady planar motion of an ideal fiber-reinforced fluid can be consolidated in a single third-order nonlinear equation. Remarkably, this equation admits a solitonic reduction related to the classical sine-Gordon equation. The kinematic conditions in this case admit a novel duality property and a Bäcklund transformation.     

Bäcklund transformations and soliton solutions for the KdV6 equation

Using Hirota technique, a Bäcklund transformation in bilinear form is obtained for the KdV6 equation. Furthermore, we present a modified Bäcklund transformation by a dependent variable transformation, it is shown that a new representation of N-soliton solution and some novel solutions to the KdV6 equation are derived by performing an appropriate limiting procedure on the known soliton solutions.     

Integrable Boundary Value Problem for the Boussinesq Equation

We discuss a method for seeking integrable boundary conditions for nonlinear equations. For the Boussinesq equation, we find a new boundary condition that is compatible with the Lax pair and has an infinite set of higher symmetries and a Bäcklund transformation. We construct a class of explicit partial solutions of an equation satisfying this boundary condition.     

Lagrangian Chains and Canonical Bäcklund Transformations

We consider Darboux transformations for operators of arbitrary order and construct the general theory of Bäcklund transformations based on the Lagrangian formalism. The dressing chain for the Boussinesq equation and its reduction are demonstrative examples for the suggested general theory. We also discuss the well-known Bäcklund transformations for classical soliton equations.     

The generalized Wronskian solutions of a inverse KdV hierarchy

A hierarchy of the inverse KdV equation is discussed. Through the bilinear form of Lax pairs, we prove a generalized Darboux-Crum theorem of the hierarchy. The Bäcklund transformation and the generalized Wronskian solutions are presented. The soliton solutions, explicit rational solutions are obtained then.     

Bäcklund transformation of nonlinear evolution equations

Using Lax pair and looking for the gauge transformation, we obtain the Bäcklund transformation in another form (sometimes it is called Darboux transformation) for some nonlinear evolution equations. We shall see that it is more convenient to use this form of Bäcklund transformation.     

Symbolic computation, Bäcklund transformation and analytic N-soliton-like solution for a nonlinear Schrödinger equation with nonuniformity term from certain space/laboratory plasmas

With symbolic computation, a bilinear Bäcklund transformation is presented for a nonlinear Schrödinger equation with nonuniformity term from certain space/laboratory plasmas, and correspondingly the one-soliton-like solution is derived from the Bäcklund transformation. Simultaneously, the N-soliton-like solution in double Wronskian form is also given. Besides, the authors verify that the (N−1)- and N-soliton-like solutions satisfy the Bäcklund transformation. The results obtained in this paper might be valuable for the study of the nonuniform media.     

An algebraic representation of the affine Bäcklund transformation

In 1980 Chern and Terng defined a Bäcklund transformation for affine minimal surfaces. In this paper we show that this Bäcklund transformation can be simply represented by an involution and translation of the affine conormal.     

On the construction of exact solutions of the stationary axially symmetric Einstein equations

Summary For the stationary axially symmetric vacuum, field, the Einstein equations reduce to a system for the logarithmic derivatives of the unknown function. An inverse scattering formula and a Bäcklund transformation are presented for the reduced system. As the simplest case, successive uses of the Bäcklund transformation give the Kasner type solutions and their generalization starting from the Minkowski metric.     

Several kinds of Bäcklund transformations of the cylindrical KdV equation which contains a zero degree termf(t)

By means of discussing the Painleve property of partial differential equations, we obtain the Lax pairs of the cylinder KdV equations with 0-th order term and some classes of Bäcklund transformations, and show that, when the 0-th order term disappears, the Bäcklund transformation of the concerned equation will then degenerate to the Bäcklund transformation of cylinder KdV equation. At the end of this paper several concrete examples are given.Project supported by the Science Fund of the Chinese Academy of Sciences.     

On RF-pairs, Bäcklund transformations and linearization of nonlinear equations

Some classes of nonlinear equations of mathematical physics are described that admit order reduction through the use of a hydrodynamic-type transformation, where the unknown function is taken as a new independent variable and an appropriate partial derivative is taken as the new dependent variable. RF-pairs and associated Bäcklund transformations are constructed for evolution equations of general form. The results obtained are used for order reduction of hydrodynamic equations (Navier-Stokes and boundary layer) and constructing exact solutions to these equations. A generalized Calogero equation and a number of other new linearizable nonlinear differential equations of the second, third and forth orders are considered. Some integro-differential equations are analyzed.     

Superposition formulae of a fifth order KdV equation and its modified equation

The Bäcklund transformation (BT) for a fifth order KdV equation is presented in the bilinear form. Furthermore, a nonlinear superposition formula related to the BT obtained above is proved rigorously. By the way, a nonlinear superposition formula of a modified fifth order KdV equation is also given.     

Bilinear Bäcklund transformation and Lax pair for a coupled Ramani equation

In this paper, a coupled Ramani equation is proposed. The bilinear Bäcklund transformation and Lax pair for this equation are derived starting from its bilinear form. Multisoliton solutions to the system can also be obtained.     

Bäcklund transformations for new fourth Painlevé hierarchies

We consider a system of equations defined using the Hamiltonian operator of the Boussinesq hierarchy, as well as two successive modifications thereof. We are able to reduce the order of these three systems and give Bäcklund transformations between the integrated equations. We also give auto-Bäcklund transformations for the two modified systems.Particular cases of two of the three equations considered correspond to generalized fourth Painlevé hierarchies and are new; these are particular cases of the two modified systems. Thus we obtain auto-Bäcklund transformations for these new fourth Painlevé hierarchies, as well as Bäcklund transformations between our hierarchies. Our results on reduction of order are also applicable in this special case, and include as a particular example a reduction of order for the scaling similarity reduction of the Boussinesq equation, a result which, remarkably, seems not to have been given previously.     

On some aspects of Bäcklund transformations

The Painlevé differential equations (P₂-P₆) possess Bäcklund transformations which relate one solution to another solution either of the same equation, with different values of the parameters, or another such equation. We review a method for deriving difference equations, the discrete Painlevé equations in particular, from Bäcklund transformations of the continuous Painlevé equations. Then, we prove the existence of an algebraic formula relating three inconsecutive solutions of the same Bäcklund hierarchy for P₃ and P₄.     

Bäcklund transformation and multi-soliton solutions for a (2 + 1)-dimensional Korteweg-de Vries system via symbolic computation

In this paper, the (2 + 1)-dimensional Korteweg-de Vries system is symbolically investigated. By the bilinear method, the N-soliton solution is presented. Then, based on the Bäcklund transformation in bilinear form, a new Bäcklund transformation is obtained and new representation of the N-soliton solution is derived. A class of novel multi-soliton solutions are obtained by the new Bäcklund transformation and the availability of symbolic computation is demonstrated.     

Lax pair, Bäcklund transformation and N-soliton-like solution for a variable-coefficient Gardner equation from nonlinear lattice, plasma physics and ocean dynamics with symbolic computation

In this paper, a generalized variable-coefficient Gardner equation arising in nonlinear lattice, plasma physics and ocean dynamics is investigated. With symbolic computation, the Lax pair and Bäcklund transformation are explicitly obtained when the coefficient functions obey the Painlevé-integrable conditions. Meanwhile, under the constraint conditions, two transformations from such an equation either to the constant-coefficient Gardner or modified Korteweg-de Vries (mKdV) equation are proposed. Via the two transformations, the investigations on the variable-coefficient Gardner equation can be based on the constant-coefficient ones. The N-soliton-like solution is presented and discussed through the figures for some sample solutions. It is shown in the discussions that the variable-coefficient Gardner equation possesses the right- and left-travelling soliton-like waves, which involve abundant temporally-inhomogeneous features.     

The decay mode solutions for the cylindrical KP equation

The decay mode solutions for the cylindrical Kadomtsev-Petviashvili equation can be obtained by the Bäcklund transformation and Hirota method.