Abstract:
We introduce a hierarchy of integrable partial differential equations in
$2+1$ dimensions arising from the commutation of one-parameter families of
vector fields, and we construct the formal solution of the associated Cauchy
problems using the inverse scattering method for one-parameter families of
vector fields. Because the space of eigenfunctions is a ring, the inverse
problem can be formulated in three distinct ways. In particular, one
formulation corresponds to a linear integral equation for a Jost
eigenfunction, and another formulation is a scalar nonlinear Riemann problem
for suitable analytic eigenfunctions.
Keywords:integrable system, inverse scattering transform, inverse spectral transformation, family of vector fields, nonlinear Riemann problem.