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An inverse scattering transform for the lattice potential KdV equation. (English) Zbl 1204.35144

Summary: The lattice potential Korteweg-de Vries equation (LKdV) is a partial difference equation in two independent variables, which possesses many properties that are analogous to those of the celebrated Korteweg-de Vries equation. These include discrete soliton solutions, Bäcklund transformations and an associated linear problem, called a Lax pair, for which it provides the compatibility condition. In this paper, we solve the initial value problem for the LKdV equation through a discrete implementation of the inverse scattering transform method applied to the Lax pair. The initial value used for the LKdV equation is assumed to be real and decaying to zero as the absolute value of the discrete spatial variable approaches large values. An interesting feature of our approach is the solution of a discrete Gel’fand-Levitan equation. Moreover, we provide a complete characterization of reflectionless potentials and show that this leads to the Cauchy matrix form of \(N\)-soliton solutions.

MSC:

35Q53 KdV equations (Korteweg-de Vries equations)
35R30 Inverse problems for PDEs
35A22 Transform methods (e.g., integral transforms) applied to PDEs
39A12 Discrete version of topics in analysis
37K35 Lie-Bäcklund and other transformations for infinite-dimensional Hamiltonian and Lagrangian systems