SQUARED EIGENFUNCTION SYMMETRIES FOR SOLITON-EQUATIONS - PART-II

Nonlinear integrable evolution equations in 1 + 1 dimensions arise fro m constraints of the 2 + 1-dimensional hierarchies associated with the Kadomtsev-Petviashvili (KP) equation, the modified KP equation and th e Dym equation, respectively. Links of Backlund type and of reciprocal type are known to exist between the 2 + 1-dimensional systems. The co rresponding links between the constrained flows are discussed in a gen eral framework. In particular, squared eigenfunction symmetries genera ted by solutions of the associated linear scattering problems are cons idered. The links between the soliton hierarchies are extended to thes e symmetries. (C) 1998 Academic Press.