ON THE SIMPLEST INTEGRABLE EQUATION IN 2+1

An integrable two-dimensional generalization of the non-linear Schrodi nger equation is discussed. This equation is the simplest scalar evolu tion equation in two dimensions, which can be integrated by the invers e spectral method. This example is used to illustrate the important fa ct that to each one-dimensional integrable equation, there correspond several two-dimensional integrable generalizations.