On Symmetry Flows of Noncommutative Kadomtsev-Petviashvili Hierarchy

We discuss symmetry flows of noncommutative Kadomtsev-Petviashvili (NCKP) hierarchy. An operatorbased formulation, alternative to the star-product approach of extended symmetry flows is presented. Noncommutative additional symmetry flows of the NCKP hierarchy are formulated. A rescaling symmetry flow which is associated with the rescaling of whole coordinates is introduced.

无色散KP系列与Dunajski方程系列的相容性

从一阶微分方程组的角度出发,证明了无色散KP系列的相容性.类似地,采取与无色散KP系列相同的方法,证明了Dunajski方程系列算子m和n的相容性.这两个相容性也是无色散KP系列和Dunajski方程系列的一个新定义.

On a Reduction of the Kadomtsev-Petviashvili Hierarchy

This paper analyzes the reduction of the well known Kadomtsev-Petviashvili hierarchy. The reduction yields a previously unknown dispersion counterpart of the dispersionless hierarchy which has a Lax function of the form p＋u（x）（p-φ）^-1＋v（x）（p-φ）^-2. This paper also describes the bihamiltonian structure of the reduced hierarchy using Dirac reduction and proves that the approximation for the reduced hierarchy up to the second order of the dispersion parameter coincides with the hierarchy of integrable systems constructed from a particular twodimensional Frobenius manifold using the approach of Dubrovin and Zhang.

无色散BKP方程族可积耦合推广及其求解

该文通过对B类Kadomtsev-Petviashvili(B type of Kadomtsev-Petviashvili,简称为BKP)方程族基于特征函数及共轭特征函数表示的对称约束取无色散极限,得到无色散BKP(dispersionless BKP,简称为dBKP)方程族的对称约束;其次,基于dBKP方程族的对称约束,考察了dBKP方程族的推广问题.通过计算推广的dBKP方程族的零曲率方程,该文导出了第一、二类型的带自相容源的dBKP方程(dispersionless BKP equation with selfconsistent sources,简称为dBKPESCS)及其相应的守恒方程.最后,利用速端变换及约化的方法求解了第一型dBKPESCS.

Block(or Hamiltonian) Lie Symmetry of Dispersionless D-Type Drinfeld–Sokolov Hierarchy

In this paper, the dispersionless D-type Drinfeld–Sokolov hierarchy, i.e. a reduction of the dispersionless two-component BKP hierarchy, is studied. The additional symmetry flows of this hierarchy are presented. These flows form an infinite-dimensional Lie algebra of Block type as well as a Lie algebra of Hamiltonian type.

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.

Recursion Operators for Dispersionless KP Hierarchy

Based on the corresponding theorem between dispersionless KP （dKP） hierarchy and h-dependent KP （hKP） hierarchy, a general formal representation of the recursion operators for dKP hierarchy under n-reduction is given in a systematical way from the corresponding hKP hierarchy. To illustrate this method, the recursion operators for dKP hierarchy under 2-reduction and 3-reduction are calculated in detail.

Collisions Between Lumps/Rogue Waves and Solitons for A(3+1)-Dimensional Generalized Variable-Coefficient Shallow Water Wave Equation

In this paper,we investigate a(3+1)-dimensional generalized variable-coefficient shallow water wave equation,which can be used to describe the flow below a pressure surface in oceanography and atmospheric science.Employing the Kadomtsev−Petviashvili hierarchy reduction,we obtain the semi-rational solutions which describe the lumps and rogue waves interacting with the kink solitons.We find that the lump appears from one kink soliton and fuses into the other on the x−y and x−t planes.However,on the x−z plane,the localized waves in the middle of the parallel kink solitons are in two forms:lumps and line rogue waves.The effects of the variable coefficients on the two forms are discussed.The dispersion coefficient influences the speed of solitons,while the background coefficient influences the background’s height.

Rogue waves of a(3+1)-dimensional BKP equation

We investigate certain rogue waves of a(3+1)-dimensional BKP equation via the Kadomtsev-Petviashili hierarchy reduction method.We obtain semi-rational solutions in the determinant form,which contain two special interactions:(i)one lump develops from a kink soliton and then fuses into the other kink one;(ii)a line rogue wave arises from the segment between two kink solitons and then disappears quickly.We find that such a lump or line rogue wave only survives in a short time and localizes in both space and time,which performs like a rogue wave.Furthermore,the higher-order semi-rational solutions describing the interaction between two lumps(one line rogue wave)and three kink solitons are presented.

Conservation laws of some soliton equations with self-consistent sources

Infinitely many conservation laws for some （1＋1）-dimension soliton hierarchy with self-consistent sources are constructed from their corresponding Lax pairs directly. Three examples are given. Besides, infinitely many conservation laws for Kadomtsev-Petviashvili （KP） hierarchy with self-consistent sources are obtained from the pseudo-differential operator and the Lax pair.

非交换无色散Gelfand-Dickey方程族的附加对称

本文主要研究非交换无色散Gelfand-Dickey(GD)方程族的附加对称,给出它的Lax函数及方程,定义Orlov-Schulman函数M和附加流.在GD方程族约束情况下,找出非交换无色散GD方程族附加流中的存活流,同时研究特殊流得到弦方程并证明其形成一个无穷维李代数W_(1+∞).

无色散p-约化KP系列的弦方程

无色散p-约化KP系列是无色散KP系列的约化形式.基于两个形式劳伦级数,由特殊的附加对称流,无色散p-约化KP系列的弦方程被给出.

N=2 Multicomponent Supersymmetric KP Hierarchy and Additional Symmetries

We study additional non-isospectral symmetries of multicomponent constrained N=2 supersymmetric Kadomtsev-Petviashvili(KP)hierarchies.These symmetries are shown to form an infinite-dimensional non-Abelian superloop superalgebra.

Bilinear Forms and Dark-Dark Solitons for the Coupled Cubic-Quintic Nonlinear Schrodinger Equations with Variable Coefficients in a Twin-Core Optical Fiber or Non-Kerr Medium

Twin-core optical fibers are applied in such fields as the optical sensing and optical communication,and propagation of the pulses,Gauss beams and laser beams in the non-Kerr media is reported.Studied in this paper are the coupled cubic-quintic nonlinear Schrodinger equations with variable coefficients,which describe the effects of quintic nonlinearity for the ultrashort optical pulse propagation in a twin-core optical fiber or non-Kerr medium.Based on the integrable conditions,bilinear forms are derived,and dark-dark soliton solutions can be constructed in terms of the Gramian via the Kadomtsev-Petviashvili hierarchy reduction.Propagation and interaction of the dark-dark solitons are presented and discussed through the graphic analysis.With different values of the delayed nonlinear response effect b(z),where z represents direction of the propagation,the linear-and parabolic-shaped one dark-dark soltions can be derived.Interactions between the parabolic-and periodic-shaped two dark-dark solitons are presented with b(z)as the linear and periodic functions,respectively.Directions of velocities of the two dark-dark solitons vary with z and the amplitudes of the solitons remain unchanged can be observed.Interactions between the two dark-dark solitons of different types are displayed,and we observe that the velocity of one soliton is zero and direction of the velocity of the other soliton vary with z.We find that those interactions are elastic.