Abstract:
We consider the hierarchy of integrable $(1+2)$-dimensional equations
related to the Lie algebra of vector fields on the line. We construct
solutions in quadratures that contain $n$ arbitrary functions of a single
argument. A simple equation for the generating function of the hierarchy,
which determines the dynamics in negative times and finds applications to
second-order spectral problems, is of main interest. Considering its
polynomial solutions under the condition that the corresponding potential is
regular allows developing a rather general theory of integrable
$(1+1)$-dimensional equations.
Keywords:hierarchy of commuting vector fields, Riemann invariant, Dubrovin equations.