The inviscid limit for the complex Ginzburg-Landau equation

We study the inviscid limit of the complex Ginzburg-Landau equation. We observe that the solutions for the complex Ginzburg-Landau equation converge to the corresponding solutions for the nonlinear Schrödinger equation. We give its convergence rate. We estimate the integral forms of solutions for two equations.     

Conditional Symmetry and Exact Solutions of a Multidimensional Diffusion Equation

We investigate the conditional symmetry of a multidimensional nonlinear reaction–diffusion equation by its reduction to a radial equation. We construct exact solutions of this equation and infinite families of exact solutions for the corresponding one-dimensional diffusion equation.     

Reduction of multidimensional first order equations with multi-homogeneous function of derivatives

We present an analysis of solutions to multidimensional first order equation order with several independent variables under assumption that the nonlinear part of the equation is a multi-homogeneous function of derivatives. The reduction of the original equation is performed for the class of solutions depending on linear combinations of prescribed groups of initial variables. We obtain solutions to the reduced equation. We consider also the cases of additional, multiplicational and combined separation of variables.     

Global existence and blow-up phenomena for a periodic 2-component Camassa–Holm equation

We first establish local well-posedness for a periodic 2-component Camassa?CHolm equation. We then present two global existence results for strong solutions to the equation. We finally obtain several blow-up results and the blow-up rate of strong solutions to the equation.     

Similarity Reductions of a Generalized Double Dispersion Equation

We apply the Lie–group formalism to deduce symmetries of a generalized double dispersion equation. We derive the ordinary differential equation to which the equation is reduced. We obtain exact solutions which can be expressed by various single and combine nondegenerative Jacobi elliptic function solutions and their degenerative solutions. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Theta Function Solutions of the Schlesinger System and the Ernst Equation

We establish a link between the Schlesinger system and the Ernst equation (the stationary axisymmetric Einstein equation) on the level of algebro-geometric solutions. We calculate all metric coefficients corresponding to general algebro-geometric solutions of the Ernst equation.     

Self-similar solutions of semilinear wave equation with variable speed of propagation

We investigate the issue of existence of the self-similar solutions of the generalized Tricomi equation in the half-space where the equation is hyperbolic. We look for the self-similar solutions via the Cauchy problem. An integral transformation suggested in [K. Yagdjian, A note on the fundamental solution for the Tricomi-type equation in the hyperbolic domain, J. Differential Equations 206 (2004) 227-252] is used to represent solutions of the Cauchy problem for the linear Tricomi-type equation in terms of fundamental solutions of the classical wave equation. This representation allows us to prove decay estimates for the linear Tricomi-type equation with a source term. Obtained in [K. Yagdjian, The self-similar solutions of the Tricomi-type equations, Z. Angew. Math. Phys., in press, doi:10.1007/s00033-006-5099-2] estimates for the self-similar solutions of the linear Tricomi-type equation are the key tools to prove existence of the self-similar solutions.     

Classical Yang-Baxter Equation and the A∞-Constraint

We show that elliptic solutions of classical Yang-Baxter equation (CYBE) can be obtained from triple Massey products on an elliptic curve. We introduce the associative version of this equation which has two spectral parameters and construct its elliptic solutions. We also study some degenerations of these solutions.     

Burgers-BBM方程新的精确解

借助两个推广形式的Riccati方程组和Mathematica软件，求出了Burgers-BBM方程，BBM方程，KDV—Burgers方程的大量新的精确解，包括各种形式的孤立波解和三角函数周期解．     

Nonautonomous differential equations in the algebra of new generalized functions

We study a nonautonomous equation with generalized coefficients in an algebra of generalized functions. The solutions of the equation can be rather different depending on the interpretation of the equation. We show that all these solutions can be obtained from the solution of this equation in the algebra of generalized functions.     

New travelling wave solutions to the Ostrovsky equation

In this work, new travelling wave solutions to the Ostrovsky equation are studied by employing the improved tanh function method. With this method, the Ostrovsky equation is reduced to the nonlinear ordinary differential equation and then the different types of exact solutions are derived based on the solutions of the Riccati equation. We will compare our solutions with those gained by the other methods.     

The variational iteration method combined with improved generalized tanh-coth method applied to Sawada-Kotera equation

We obtain new exact solutions to generalized Sawada-Kotera equation. Using the variational iteration method combined with the improved generalized tanh-coth method, we construct new traveling wave solutions for the standard Sawada-Kotera equation and, by means of scaling, we obtain new solutions to general Sawada-Kotera equation. Periodic and soliton solutions are formally derived for both models.     

Approximations of Solutions to Abstract Neutral Functional Differential Equation

In the present work, we study the approximations of solutions to the abstract neutral functional differential equations with bounded delay. We consider an associated integral equation and a sequence of approximate integral equations. We establish the existence and uniqueness of the solutions to every approximate integral equation using the fixed point arguments. We then prove the convergence of the solutions of the approximate integral equations to the solution of the associated integral equation. Next, we consider the Faedo–Galerkin approximations of the solutions and prove some convergence results. Finally, we demonstrate the application of the results established.     

Reduction method for studying localized solutions of neural field equations on the Poincaré disk

We present a reduction method to study localized solutions of an integrodifferential equation defined on the Poincaré disk. This equation arises in a problem of texture perception modeling in the visual cortex. We first derive a partial differential equation which is equivalent to the initial integrodifferential equation and then deduce that localized solutions which are radially symmetric satisfy a fourth order ordinary differential equation.     

A new integrable equation that combines the KdV equation with the negative‐order KdV equation

In this work, we develop a new integrable equation by combining the KdV equation and the negative‐order KdV equation. We use concurrently the KdV recursion operator and the inverse KdV recursion operator to construct this new integrable equation. We show that this equation nicely passes the Painlevé test. As a result, multiple soliton solutions and other soliton and periodic solutions are guaranteed and formally derived.     

A note on “New kink-shaped solutions and periodic wave solutions for the (2 + 1)-dimensional Sine-Gordon equation”

Exact solutions of the Nizhnik-Novikov-Veselov equation by Li [New kink-shaped solutions and periodic wave solutions for the (2 + 1)-dimensional Sine-Gordon equation, Appl. Math. Comput. 215 (2009) 3777-3781] are analyzed. We have observed that fourteen solutions by Li from 30 do not satisfy the equation. The other 16 exact solutions by Li can be found from the general solutions of the well-known solution of the equation for the Weierstrass elliptic function.     

Uniqueness of solutions for the extended Fisher-Kolmogorov equation

We consider stationary solutions of the Extended Fisher-Kolmogorov (EFK) equation, a fourth-order model equation for bi-stable systems. We show that as long as the stable equilibrium points are real saddles, the paths in the (u, u')-plane of two bounded solutions do not cross. As a consequence we derive that the bounded solutions of the EFK equation correspond exactly to those of the classical Fisher-Kolmogorov equation.     

Planar nonautonomous polynomial equations: The Riccati equation

We give a few sufficient conditions for the existence of two periodic solutions of the Riccati ordinary differential equation in the plane. We give also examples of the equation without periodic solutions.     

Stability of the line soliton of the KP-II equation under periodic transverse perturbations

We prove the nonlinear stability of the KdV solitary waves considered as solutions of the KP-II equation, with respect to periodic transverse perturbations. Our proof uses a Miura transform which sends the solutions of an mKP-II equation to solutions of the KP-II equation.     

Radial equivalence for the two basic nonlinear degenerate diffusion equations

In this paper we prove that there exists an explicit correspondence between the radially symmetric solutions of two well-known models of nonlinear diffusion, the porous medium equation and the p-Laplacian equation. We establish exact correspondence formulas between these solutions. We also study in detail the application of the results in the important case of self-similar solutions. In particular, we derive the existence of new self-similar solutions for the evolution p-Laplacian equation.