The Delsarte-Darboux type binary transformations and their   differential-geometric and operator structure. Part 1
  The structure properties of multidimensional Delsarte-Darboux transmutation operators in parametric functional spaces is studied by means of differential-geometric and topological tools. It is shown that kernels of the corresponding integral operator expressions depend on the topological structure of related homological cycles in the coordinate space. As a natural realization of the construction presented we build pairs of Lax type commutative differential operator expressions related via a Delsarte-Darboux transformation and having a lot of applications in soliton theory. 
Y.A. Prykarpatsky, A.M. Samoilenko, A.K. Prykarpatsky, V.Hr.   Samoylenko