A survey of the spectral and differential geometric aspects of the De   Rham-Hodge-Skrypnik theory related with Delsarte transmutation operators in   multidimension and its applications to spectral and soliton problems. Part 2
  The differential-geometric and topological structure of Delsarte transmutation operators and associated with them Gelfand-Levitan-Marchenko type eqautions are studied making use of the De Rham-Hodge-Skrypnik differential complex. The relationships with spectral theory and special Berezansky type congruence properties of Delsarte transmuted operators are stated. Some applications to multidimensional differential operators are done including three-dimensional Laplace operator, two-dimensional classical Dirac operator and its multidimensional affine extension, related with self-dual Yang-Mills eqautions. The soliton like solutions to the related set of nonlinear dynamical systemare discussed. 
Y.A. Prykarpatsky, A.M. Samoilenko, A. K. Prykarpatsky