Operator identities corresponding to inverse problems
  The structured operators and corresponding operator identities, which appear in inverse problems for the self-adjoint and skew-self-adjoint Dirac systems with rectangular potentials, are studied in detail. In particular, it is shown that operators with the close to displacement kernels are included in this class. A special case of positive and factorizable operators is dealt with separately. 
B. Fritzsche, B. Kirstein, I.Ya. Roitberg, A.L. Sakhnovich
math.FA math.CA