The Peakon Limit of the N-Soliton Solution of the Camassa-Holm Equation

Abstract

We show that the analytic N-soliton solution of the Camassa-Holm (CH) shallow-water model equation converges to the nonanalytic N-peakon solution of the dispersionless CH equation when the dispersion parameter tends to zero. To demonstrate this, we develop a novel limiting procedure and apply it to the parametric representation for the N-soliton solution of the CH equaiton. In the process, we use Jacobi's formula for determinants as well as various identities among the Hankel determinants to facilitate the asymptotic analysis. We also provide a new representation of the N-peakon solution in terms of the Hankel determinants.