  Quasiclassical generalized Weierstrass representation (GWR) for highly
corrugated surfaces with slow modulation in the four-dimensional Euclidean
space is proposed. Integrable deformations of such surfaces are described by
the dispersionless Davey-Stewartson hierarchy. Quasiclassical GWRs for other
four-dimensional spaces and dispersionless DS system are discussed too.

Exactly Solvable and Integrable Systems;Differential Geometry