Pfaffianization of the variable-coefficient Kadomtsev-Petviashvili equation＊

This paper constructs more general exact solutions than $N$-soliton solution and Wronskian solution for variable-coefficient Kadomtsev--Petviashvili (KP) equation. By using the Hirota method and Pfaffian technique, it finds the Grammian determinant-type solution for the variable-coefficient KP equation (VCKP), the Wronski-type Pfaffian solution and the Gram-type Pfaffian solutions for the Pfaffianized VCKP equation.     

Grammian Determinant Solution and Pfaffianization for a （3＋1）-Dimensional Soliton Equation

Based on the Pfaffian derivative formulae, a Grammian determinant solution for a （3＋1）-dimensional soliton equation is obtained. Moreover, the Pfaffianization procedure is applied for the equation to generate a new coupled system. At last, a Gram-type Pfaffian solution to the new coupled system is given.     

Wronskian and Grammian Determinant Solutions for a Variable-Coefficient Kadomtsev-Petviashvili Equation

In this paper, we derive the bilinear form for a variable-coefficient Kadomtsev Petviashvili-typed equation. Based on the bilinear form, we obtain the Wronskian determinant solution, which is proved to be indeed an exact solution of this equation through the Wronskian technique. In addition, we testify that this equation can be reduced to a Jacobi identity by considering its solution as a Grammian determinant by means of Pfaffian derivative formulae.     

Grammian Determinant Solution and Pfaffianization for a (3+1)-Dimensional Soliton Equation

Based on the Pfaffian derivative formulae, a Grammian determinant solution for a (3+1)-dimensional soliton equation is obtained. Moreover, the Pfaffianization procedure is applied for the equation to generate a new coupled system. At last, a Gram-type Pfaffian solution to the new coupled system is given.     

Grammian Solutions to a Variable-Coefficient KP Equation

Solutions in the Grammian form for a variable-coefficient Kadomtsev-Petviashvili （KP） equation which has the Wronskian solutions are derived by means of Pfaffian derivative formulae.     

Grammian solutions and Pfaffianization of the non-isospectral modified Kadomtsev-Petviashvili equation

The Grammian determinant solutions of the non-isospectral modified Kadomtsev-Petviashvili (mKP) equation are presented. Moreover, a new non-isospectral coupled system is constructed by using the Pfaffianization procedure. Furthermore, Gramm-type Pfaffian solutions of the non-isospectral coupled system are obtained.     

Generalized Wronskian and Grammian Solutions to a Isospectral B-type Kadomtsev-Petviashvili equation

Generally speaking, the BKP hierarchy which only has Pfaffian solutions. In this paper, based on the Grammian and Wronskian derivative formulae, generalized Wronskian and Grammian determinant solutions are obtained for the isospectral BKP equation (the second member on the BKP hierarchy) in the Hirota bilinear form. Especially, with the help of the properties of the computing of Young diagram, we have first applied Young diagram proved the proposition of this paper. Moreover, by considering the different combinations of the entries in Wronskian, we obtain various types of Wronskian solutions.     

Soliton Solutions for Nonisospectral BKP Equation

The soliton solutions for the nonisospeetral BKP equation are derived through Hirota method and Pfaffian technique. We also derive the bilinear Baeklund transformations for the isospectral and nonisospeetral BKP equation and find solutions with the help of the obtained bilinear Baeklund transformations.     

Pfaffian Solutions and Resonant Interaction Properties of a Coupled BKP Lattice

In this paper, we give a coupled lattice equation with the help of Hirota operators, which comes from a special BKP lattice. Two-soliton and three-soliton solutions to the coupled system are constructed. Furthermore,resonant interaction of the two-soliton solution is analyzed in detail. Under some special resonant condition, it is shown that low soliton can propagate faster than high one. Finally, the N-soliton solution is presented in the Pfaffian form.     

Pfaffian Solutions and Resonant Interaction Properties of a Coupled BKP Lattice

In this paper, we give a coupled lattice equation with the help of Hirota operators, which comes from a special BKP lattice. Two-soliton and three-soliton solutions to the coupled system are constructed. Furthermore, resonant interaction of the two-soliton solution is analyzed in detail. Under some special resonant condition, it is shown that low soliton can propagate faster than high one. Finally, the N-soliton solution is presented in the Pfaffian form.     

Wronskian and Grammian solutions for (3+1)-dimensional Jimbo–Miwa equation

In this paper, based on the Hirota's bilinear method, the Wronskian and Grammian technique, as well as several properties of determinant, a broad set of sufficient conditions consisting of systems of linear partial differential equations are presented, which guarantees that the Wronskian determinant and the Grammian determinant solve the (3+1)-dimensional Jimbo-Miwa equation in the bilinear form, and then some special exact Wronskian and Grammian solutions are obtained by solving the differential conditions. At last, with the aid of Maple, some of these special exact solutions are shown graphically.     

Wronskian and Grammian solutions for the （3＋ 1）-dimensional Jimbo-Miwa equation

<正>In this paper,based on Hirota’s bilinear method,the Wronskian and Grammian techniques,as well as several properties of the determinant,a broad set of sufficient conditions consisting of systems of linear partial differential equations are presented.They guarantee that the Wronskian determinant and the Grammian determinant solve the (3 + 1)-dimensional Jimbo-Miwa equation in the bilinear form.Then some special exact Wronskian and Grammian solutions are obtained by solving the differential conditions.At last,with the aid of Maple,some of these special exact solutions are shown graphically.     

The discrete variational principle and the first integrals of Birkhoff systems＊

This paper shows that first integrals of discrete equation of motion for Birkhoff systems can be determined explicitly by investigating the invariance properties of the discrete Pfaffian. The result obtained is a discrete analogue of theorem of Noether in the calculus of variations. An example is given to illustrate the application of the results.     

Extended Determinant Solution of a （3 ＋ 1）-Dimensional KP Equation

In this paper, new extended Grammian determinant solutions to a （3 ＋ 1）-dimensional KP equation are presented by using Hirora＇s bilinear method, and a broad set of suftlcient conditions of systems of linear partial differential equations is given. Moreover, some special solutions of the representative systems are obtained through a systematic analysis.     

Grammian Solutions to a Non-Isospectral Kadomtsev-Petviashvili Equation

Solutions in the Crammian form for a non-isospectral Kadomtsev-Petviashvili equation are derived by means of Pfaffian derivative formulae. Explicit entries of the Crammian are given. Non-isospectral dynamics of the solutions generated from the Crammian are investigated in an analytic way. The solutions obtained can describe line solitons in non-uniform media travelling with time-dependent amplitude and time-dependent direction. In addition, some other solutions have singularities.     

Multisoliton Solutions for the Isospectral and Nonisospectral BKP Equation with Self-Consistent Sources

The isospectral and nonisospectral BKP equation with self-consistent sources is derived to study the linear problem of the BKP system. The bilinear form of the nonisospeetral BKP equation with self-consistent sources is given and the N-soliton solutions are obtained with the Hirota method and Pfaffian technique, respectively.     

事件空间中Birkhoff系统的Noether理论

研究事件空间中Birkhoff系统的Noether对称性与Noether守恒量.首先,建立了事件空间中Birkhoff系统的参数方程;其次,基于Pfaff作用量在无限小变换下的不变性,给出了事件空间中Birkhoff系统的Noether定理及其逆定理;最后,举例说明结果的应用. 关键词： 事件空间 Birkhoff系统 Pfaff作用量 Noether对称性     

Classical thermodynamics formulated as a field theory in the representative space

Summary The classical equations of thermodynamics are here rewritten in the form of a field equation in then-dimensional space of the state variables. This result is obtained by proving the validity of a theorem for Pfaffian forms inn-dimensional spaces. By using the field expression thus obtained, it becomes possible to reformulate classical thermodynamics in a very compact way. Due to the relevance of its scientific content, this paper has been given priority by the Journal Direction.     

Dimer statistics of honeycomb lattices on Klein bottle,Möbius strip and cylinder

Dimer statistics is a central problem in statistical physics. In this paper the enumerations of close-packed dimers of honeycomb lattices on Klein bottle, Möbius strip and cylinder are considered. By establishing a Pfaffian orientation or a crossing orientation, and then computing the determinants of the skew-symmetric matrices of the resulting orientation graphs, we obtain explicit expressions of the number of close-packed dimers of the Klein-bottle polyhex, the Möbius polyhex and the cylindrical polyhex.     

Exact solutions of the generalized Bretherton equation

The generalized Bretherton equation is studied. The Bäcklund transformations between traveling wave solutions of the generalized Bretherton equation and solutions of polynomial ordinary differential equation are constructed. The classification problem for meromorphic solutions of the latter equation is discussed. Several new families of exact solutions for the generalized Brethenton equation are given.