Abstract:
The existence of a nontrivial integral and a sufficiently large set of symmetries with respect to one of the characteristics of a hyperbolic equation implies the existence of nontrivial integrals and symmetries with respect to the other characteristic. We classify differential substitutions of the form w=P(x,u,ux) relating families of evolution equations that depend on an arbitrary function. Among such substitutions, there are infinitely many pairwise-nonequivalent ones.
Citation:
S. Ya. Startsev, “Differential substitutions of the Miura transformation type”, TMF, 116:3 (1998), 336–348; Theoret. and Math. Phys., 116:3 (1998), 1001–1010