An integrable (2+1)-dimensional Camassa-Holm hierarchy with peakon solutions

In this letter, we propose a (2+1)-dimensional generalized Camassa-Holm (2dgCH) hierarchy with both quadratic and cubic nonlinearity. The Lax representation and peakon solutions for the 2dgCH system are derived

Persistence Properties and Unique Continuation for a Dispersionless Two-Component Camassa-Holm System with Peakon and Weak Kink Solutions

In this paper, we study the persistence properties and unique continuation for a dispersionless two-component system with peakon and weak kink solutions. These properties guarantee strong solutions of the two-component system decay at infinity in the spatial variable provided that the initial data satisfies the condition of decaying at infinity. Furthermore, we give an optimal decaying index of the momentum for the system and show that the system exhibits unique continuation if the initial momentum $m_0$ and $n_0$ are non-negative

On Negative Order KdV Equations

In this paper, based on the regular KdV system, we study negative order KdV (NKdV) equations about their Hamiltonian structures, Lax pairs, infinitely many conservation laws, and explicit multi-soliton and multi-kink wave solutions thorough bilinear B\"{a}cklund transformations. The NKdV equations studied in our paper are differential and actually derived from the first member in the negative order KdV hierarchy. The NKdV equations are not only gauge-equivalent to the Camassa-Holm equation through some hodograph transformations, but also closely related to the Ermakov-Pinney systems, and the Kupershmidt deformation. The bi-Hamiltonian structures and a Darboux transformation of the NKdV equations are constructed with the aid of trace identity and their Lax pairs, respectively. The single and double kink wave and bell soliton solutions are given in an explicit formula through the Darboux transformation. The 1-kink wave solution is expressed in the form of $tanh$ while the 1-bell soliton is in the form of $sech$, and both forms are very standard. The collisions of 2-kink-wave and 2-bell-soliton solutions, are analyzed in details, and this singular interaction is a big difference from the regular KdV equation. Multi-dimensional binary Bell polynomials are employed to find bilinear formulation and B\"{a}cklund transformations, which produce $N$-soliton solutions. A direct and unifying scheme is proposed for explicitly building up quasi-periodic wave solutions of the NKdV equations. Furthermore, the relations between quasi-periodic wave solutions and soliton solutions are clearly described. Finally, we show the quasi-periodic wave solution convergent to the soliton solution under some limit conditions.Comment: 61 pages, 4 figure

A new two-component integrable system with peakon solutions

A new two-component system with cubic nonlinearity and linear dispersion: \begin{eqnarray*} \left\{\begin{array}{l} m_t=bu_{x}+\frac{1}{2}[m(uv-u_xv_x)]_x-\frac{1}{2}m(uv_x-u_xv), \\ n_t=bv_{x}+\frac{1}{2}[ n(uv-u_xv_x)]_x+\frac{1}{2} n(uv_x-u_xv), \\m=u-u_{xx},~~ n=v-v_{xx}, \end{array}\right. \end{eqnarray*} where $b$ is an arbitrary real constant, is proposed in this paper. This system is shown integrable with its Lax pair, bi-Hamiltonian structure, and infinitely many conservation laws. Geometrically, this system describes a nontrivial one-parameter family of pseudo-spherical surfaces. In the case $b=0$, the peaked soliton (peakon) and multi-peakon solutions to this two-component system are derived. In particular, the two-peakon dynamical system is explicitly solved and their interactions are investigated in details. Moreover, a new integrable cubic nonlinear equation with linear dispersion \begin{eqnarray*} m_t=bu_{x}+\frac{1}{2}[m(|u|^2-|u_x|^2)]_x-\frac{1}{2}m(uu^\ast_x-u_xu^\ast), \quad m=u-u_{xx}, \end{eqnarray*} is obtained by imposing the complex conjugate reduction $v=u^\ast$ to the two-component system. The complex valued $N$-peakon solution and kink wave solution to this complex equation are also derived

Alice-Bob Peakon Systems

In this letter, we study the Alice-Bob peakon system generated from an integrable peakon system through using the strategy of the so-called Alice-Bob non-local KdV approach [13]. Non-local integrable peakon equations are obtained and shown to have peakon solutions.Comment: 3 figure

Analyticity, Gevrey regularity and unique continuation for an integrable multi-component peakon system with an arbitrary polynomial function

In this paper, we study the Cauchy problem for an integrable multi-component (2N-component) peakon system which is involved in an arbitrary polynomial function. Based on a generalized Ovsyannikov type theorem, we first prove the existence and uniqueness of solutions for the system in the Gevrey-Sobolev spaces with the lower bound of the lifespan. Then we show the continuity of the data-to-solution map for the system. Furthermore, by introducing a family of continuous diffeomorphisms of a line and utilizing the fine structure of the system, we demonstrate the system exhibits unique continuation

Multi-component generalization of Camassa-Holm equation

In this paper, we propose a multi-component system of Camassa-Holm equation, denoted by CH($N$,$H$) with 2N components and an arbitrary smooth function $H$. This system is shown to admit Lax pair and infinitely many conservation laws. We particularly study the case of N=2 and derive the bi-Hamiltonian structures and peaked soliton (peakon) solutions for some examples

Global existence and propagation speed for a generalized Camassa-Holm model with both dissipation and dispersion

In this paper, we study a generalized Camassa-Holm (gCH) model with both dissipation and dispersion, which has (N + 1)-order nonlinearities and includes the following three integrable equations: the Camassa-Holm, the Degasperis-Procesi, and the Novikov equations, as its reductions. We first present the local well-posedness and a precise blow-up scenario of the Cauchy problem for the gCH equation. Then we provide several sufficient conditions that guarantee the global existence of the strong solutions to the gCH equation. Finally, we investigate the propagation speed for the gCH equation when the initial data is compactly supported

The Camassa-Holm hierarchy, related N-dimensional integrable systems, and algebro-geometric solution on a symplectic submanifold

This paper shows that the Camassa-Holm (CH) spectral problem yields two different integrable hierarchies of nonlinear evolution equations (NLEEs), one is of negative order CH hierachy while the other one is of positive order CH hierarchy. The two CH hierarchies possess the zero curvature representations through solving a key matrix equation. We find that the well-known CH equation is included in the negative order CH hierarchy while a Dym type equation is included in the positive order CH hierarchy. Furthermore, under two constraint conditions between the eigenfunctions and the potentials, the CH spectral problem is cast in: (enumerate) a new Neumann-like N-dimensional system when it is restricted into a symplectic submanifold of $\R^{2N}$ which is proven to be integrable by using the Dirac-Poisson bracket and the r-matrix process; and a new Bargmann-like N-dimensional system when it is considered in the whole $\R^{2N}$ which is proven to be integrable by using the standard Poisson bracket and the r-matrix process. (enumerate) In the paper, we present two $4\times4$ instead of $N\times N$ r-matrix structures. One is for the Neumann-like CH system (not the peaked CH system), while the other one is for the Bargmann-like CH system. The whole CH hierarchy (both positive and negative order) is shown to have the parametric solution which obey the constraint relation. In particular, the CH equation constrained to some symplectic submanifold, and the Dym type equation have the parametric solutions. Moreover, we see that the kind of parametric solution of the CH equation is not gauge equivalent to the peakons. Solving the parametric representation of solution on the symplectic submanifold gives a class of new algebro-geometric solution of the CH equation.Comment: 44 pages, 0 figure

Integrable hierarchy, 3×33\times 3 constrained systems, and parametric and peaked stationary solutions

This paper gives a new integrable hierarchy of nonlinear evolution equations. The DP equation: $m_t+um_x+3mu_x=0, m=u-u_{xx}$, proposed recently by Desgaperis and Procesi \cite{DP[1999]}, is the first one in the negative hierarchy while the first one in the positive hierarchy is:\ $m_t=4(m^{-{2/3}})_x-5(m^{-{2/3}})_{xxx}+ (m^{-{2/3}})_{xxxxx}$. The whole hierarchy is shown Lax-integrable through solving a key matrix equation. To obtain the parametric solutions for the whole hierarchy, we separatedly discuss the negative and the positive hierarchies. For the negative hierarchy, its $3\times3$ Lax pairs and corresponding adjoint representations are nonlinearized to be Liouville-integrable Hamiltonian canonical systems under the so-called Dirac-Poisson bracket defined on a symplectic submanifold of $\R^{6N}$. Based on the integrability of those finite-dimensional canonical Hamiltonian systems we give the parametric solutions of the all equations in the negative hierarchy. In particular, we obtain the parametric solution of the DP equation. Moreover, for the positive hierarchy, we consider the different constraint and use a similar procudure to the negative case to obtain the parametric solutions of the positive hierarchy. In particular, we give the parametric solution of the 5th-order PDE $m_t=4(m^{-{2/3}})_x-5(m^{-{2/3}})_{xxx}+ (m^{-{2/3}})_{xxxxx}$. Finally, we discuss the stationary solutions of the 5th-order PDE, and particularly give its four peaked stationary solutions. The stationary solutions may be included in the parametric solution, but the peaked stationary solutions not. The 5th-order PDE does not have the cusp soliton although it looks like a higher order Harry-Dym equation.Comment: 23 pages, 1 figur