Recursion Operators of Some Equations of Hydrodynamic Type

Abstract

We give a general method for constructing recursion operators for some equations of hydrodynamic type, admitting a nonstandard Lax representation. We give several examples for N=2 and N=3 containing the equations of shallow water waves and its generalizations with their first two higher symmetries and their recursion operators. We also discuss a reduction of $N+1$ systems to $N$ systems of some new equations of hydrodynamic type.