An Inversion Formula and Its Application to Soliton Theory

Transformations are much used to connect complicated nonlinear differential equations to simple equations with known exact solutions. Two examples of this are the Hopf–Cole transformation and the simple equations method. In this article, we follow an idea that is opposite to the idea of Hopf and Cole: we use transformations in order to transform simpler linear or nonlinear differential equations (with known solutions) to more complicated nonlinear differential equations. In such a way, we can obtain numerous exact solutions of nonlinear differential equations. We apply this methodology to the classical parabolic differential equation (the wave equation), to the classical hyperbolic differential equation (the heat equation), and to the classical elliptic differential equation (Laplace equation). In addition, we use the methodology to obtain exact solutions of nonlinear ordinary differential equations by means of the solutions of linear differential equations and by means of the solutions of the nonlinear differential equations of Bernoulli and Riccati. Finally, we demonstrate the capacity of the methodology to lead to exact solutions of nonlinear partial differential equations on the basis of known solutions of other nonlinear partial differential equations. As an example of this, we use the Korteweg–de Vries equation and its solutions. Traveling wave solutions of nonlinear differential equations are of special interest in this article. We demonstrate the existence of the following phenomena described by some of the obtained solutions: (i) occurrence of the solitary wave–solitary antiwave from the solution, which is zero at the initial moment (analogy of an occurrence of particle and antiparticle from the vacuum); (ii) splitting of a nonlinear solitary wave into two solitary waves (analogy of splitting of a particle into two particles); (iii) soliton behavior of some of the obtained waves; (iv) existence of solitons which move with the same velocity despite the different shape and amplitude of the solitons.

<i>Self-Similarity and Beyond: Exact Solutions of Nonlinear Problems</i>

Operators with regular singularities. One variable case - Operators with regular singularities. Several variables case - Formal and convergent solutions of singular partial differential equations - Local study of differential equations of the form xy' f(x,y) near x 0 - Holomorphic and singular solutions of non linear singular first order partial differential equations - Maillet's type theorems for non linear singular partial differential equations - Maillet's type theorems for non linear singular partial differential equations without linear part - Holomorphic and singular solutions of non linear singular partial differential equations - On the existence of holomorphic solutions of the Cauchy problem for non linear partial differential equations - Maillet's type theorems for non linear singular integro-differential equations.

In this article, we use the Adomain decomposition method to find the approximate solutions for the linear and nonlinear partial fractional differential equations via the nonlinear Schrodinger partial fractional differential equation and the telegraph partial fractional differential equation. The fractional derivatives are described in the Caputo sense. We compare between the approximate solutions and the exact solutions for the partial fractional differential equations when α,β→1. Also we make the Figures to compare between the approximate solutions and the exact solutions for the partial fractional differential equations when α,β→1. This method is powerfull to find the approximate solutions for nonlinear partial fractional differential equations. Also we will compare between the approximate solutions which obtained by using the variational itearation method and the approximate solutions which obtained by Adomain decomposition methods.

In this article, the solutions of higher nonlinear partial differential equations (PDEs) with the Caputo operator are presented. The fractional PDEs are modern tools to model various phenomena more accurately. The residual power series method (RPSM) is used for the solution analysis of fractional partial differential equations (FPDEs), which has direct implementation for the solutions of fractional partial differential equations. In this work, the solutions to a few nonlinear FPDEs are handled by the proposed technique. The general and particular schemes of RPSM are constructed and implemented successfully. The fractional solutions of PDEs have provided many useful dynamics of the targeted problems. The RPSM results for both integer and fractional-order FPDEs are further explained and elaborated by using graphs and tables. It is observed that the higher accuracy of RPSM is achieved with fewer calculations. Graphs and tables for fractional-order solutions are presented, which confirm the convergence phenomena of fractional solutions toward integer order solutions of each problem. The suggested method can be extended to the solutions of other nonlinear fractional partial differential equations.

Solution of nonlinear partial differential equations from base equations

Differential quadrature: A technique for the rapid solution of nonlinear partial differential equations

We investigate the existence and Borel summability of formal power series in one variable with holomorphic coefficients, solutions of nonlinear partial differential equations with shrinkings having non-Kowalewski type in the complex domain. Sufficient conditions are given in terms of the shape of the functional partial differential equations and initial conditions. The existence and asymptotic behavior of local sectorial holomorphic solutions of these nonlinear functional partial differential equations are obtained as a by-product. We apply the results to the study of asymptotic the behavior of solutions of some advanced-argument partial differential equations in a neighborhood of infinity.

Series solution is obtained on solving non-linear fractional partial differential equation using homotopy perturbation transformation method. First of all, we apply homotopy perturbation transformation method to obtain the series solution of non-linear fractional partial differential equation. In this case, the fractional derivative is described in Caputo sense. Then, we present the facts obtained by analyzing the convergence of this series solution. Finally, the established fact is supported by an example.

The series solutions of the random nonlinear partial differential equations have been examined by a hybrid method. The random nonlinear partial differential equations are studied by both normal and uniform distributions. Two initial-value problems are indicated to exemplify the influence of the solutions acquired by the hybrid method. Also, the functions for the first and second moments of the approximate solutions of random nonlinear partial differential equations are acquired in the MAPLE software. The hybrid method is implemented to analyze the solutions of the random nonlinear partial differential equations. MAPLE software is used to find the solutions. Besides, MAPLE software is used for the drawing the figures.

Exact solutions of nonlinear differential equations are of great importance to the theory and practice of complex systems. The main point of this review article is to discuss a specific methodology for obtaining such exact solutions. The methodology is called the SEsM, or the Simple Equations Method. The article begins with a short overview of the literature connected to the methodology for obtaining exact solutions of nonlinear differential equations. This overview includes research on nonlinear waves, research on the methodology of the Inverse Scattering Transform method, and the method of Hirota, as well as some of the nonlinear equations studied by these methods. The overview continues with articles devoted to the phenomena described by the exact solutions of the nonlinear differential equations and articles about mathematical results connected to the methodology for obtaining such exact solutions. Several articles devoted to the numerical study of nonlinear waves are mentioned. Then, the approach to the SEsM is described starting from the Hopf-Cole transformation, the research of Kudryashov on the Method of the Simplest Equation, the approach to the Modified Method of the Simplest Equation, and the development of this methodology towards the SEsM. The description of the algorithm of the SEsM begins with the transformations that convert the nonlinearity of the solved complicated equation into a treatable kind of nonlinearity. Next, we discuss the use of composite functions in the steps of the algorithms. Special attention is given to the role of the simple equation in the SEsM. The connection of the methodology with other methods for obtaining exact multisoliton solutions of nonlinear differential equations is discussed. These methods are the Inverse Scattering Transform method and the Hirota method. Numerous examples of the application of the SEsM for obtaining exact solutions of nonlinear differential equations are demonstrated. One of the examples is connected to the exact solution of an equation that occurs in the SIR model of epidemic spreading. The solution of this equation can be used for modeling epidemic waves, for example, COVID-19 epidemic waves. Other examples of the application of the SEsM methodology are connected to the use of the differential equation of Bernoulli and Riccati as simple equations for obtaining exact solutions of more complicated nonlinear differential equations. The SEsM leads to a definition of a specific special function through a simple equation containing polynomial nonlinearities. The special function contains specific cases of numerous well-known functions such as the trigonometric and hyperbolic functions and the elliptic functions of Jacobi, Weierstrass, etc. Among the examples are the solutions of the differential equations of Fisher, equation of Burgers-Huxley, generalized equation of Camassa-Holm, generalized equation of Swift-Hohenberg, generalized Rayleigh equation, etc. Finally, we discuss the connection between the SEsM and the other methods for obtaining exact solutions of nonintegrable nonlinear differential equations. We present a conjecture about the relationship of the SEsM with these methods.

In this article, we use fractional sub-equation method to find the exact solutions for some nonlinear partial fractional differential equations, namely space–time fractional coupled Sakharov–Kuznetsov (Z–K) equations, space–time fractional nonlinear coupled Korteweg de Vries (KdV) equations and space–time fractional Hirota–Satsuma KdV system. As a result, three families of exact analytical solutions are obtained. Proposed method is more effective and powerful to construct the exact solutions for nonlinear partial fractional differential equations. Also, we use fractional complex transform and exp function method to find some of the exact solutions for nonlinear partial fractional differential equations.

We discuss the Simple Equations Method (SEsM) for obtaining exact solutions of nonlinear partial differential equations. We show that specific case of SEsM can be used in order to reproduce the methodology of the Inverse Scattering Transform Method for the case of the Burgers equation and Korteweg - de Vries equation. This specific case is connected to use of a specific case of Step. 2 of SEsM: representation of the solution of the solved nonlinear partial differential equation as expansion as power series containing powers of a "small" parameter ε, solving the differential equations occurring from this representation by means of Fourier series and transition from the obtained solution for small values of ε to solution for arbitrary finite values of ε. Next, we discuss the application of composite functions in SEsM. We proof two propositions connected to obtaining solutions of nonlinear differential equations with polynomial nonlinearities by means of use of composite functions. We present several examples of applications of this methodology and obtain exact solutions of the generalized Korteweg - deVries equation, Olver equation, and several other equations. Next we discuss the most simple version of SEsM: the Modified Method of Simplest Equation (MMSE). We start with the role of the simplest equation and discuss the several cases of simplest equations such as nonlinear ordinary differential equations called Riccati equation and Bernoulli equation. The theory is illustrated by obtaining exact solution of various nonlinear partial differential equations such as Newel-Whitehead equation, FitzHugh-Nagumo equation, etc. MMSE is further illustrated by obtaining exact solutions of many equations such as Swift-Hohenberg equation, Rayleigh equation, Huxley equation. Special attention is given to the process of obtaining of balance equations in the MMSE. This process is illustrated by obtaining balance equations for several model nonlinear differential equations from the area of ecology and population dynamics. Among the discussed examples are the reaction-diffusion equation with density-dependent diffusion as well as the reaction-telegraph equation. Finally we obtain exact solution of two nonlinear model differential equations connected to the water wave propagation. These are the extended Korteweg-de Vries equation and the generalized Camassa-Holm equation. We close the discussion by several remark on the methodology and about the future plans connected to our research in this area.

New wavelet based full-approximation scheme for the numerical solution of nonlinear elliptic partial differential equations

In this survey, results on the existence, growth, uniqueness, and value distribution of meromorphic (or entire) solutions of linear partial differential equations of the second order with polynomial coefficients that are similar or different from that of meromorphic solutions of linear ordinary differential equations have been obtained. We have characterized those entire solutions of a special partial differential equation that relate to Jacobian polynomials. We prove a uniqueness theorem of meromorphic functions of several complex variables sharing three values taking into account multiplicity such that one of the meromorphic functions satisfies a nonlinear partial differential equations of the first order with meromorphic coefficients, which extends the Brosch’s uniqueness theorem related to meromorphic solutions of nonlinear ordinary differential equations of the first order.