摘 要: |
We construct reciprocal transformations for the first negative flows in the hierarchies of the KdV, the mKdV, the Kaup-Kupershmidt, the Sawada-Kotera, the Fordy-Gbbons, the Boussinesq and a modified Boussinesq (or their reductions). We discuss their relations with the Camassa-Holm type equations, the generalized short pulse equations and some other equations. |