On the relation between the bicomplex and bilocal formalism for KP systems

From the MR review by B.N.Fil: "The relation between the bilocal (due to Fokas and Santini) and bicomplex approaches for nonlinear integrable equations is discussed. On the basis of the abstract algebraic theory of the Lenard bicomplex, an iterative scheme for the second formulation of the KP chain is explicitly constructed. A "fixed step'' formula, which is the true analogue of the classical recursion formula in (1+1) dimensions, is deduced. From a suitable formulation of the Lenard bicomplex a bilocal formulation of the bicomplex which is closely related to the Fokas Santini scheme is obtained directly."