Weyl theory and explicit solutions of direct and inverse problems for a   Dirac system with rectangular matrix potential
  A non-classical Weyl theory is developed for Dirac systems with rectangular matrix potentials. The notion of the Weyl function is introduced and the corresponding direct problem is treated. Furthermore, explicit solutions of the direct and inverse problems are obtained for the case of rational Weyl matrix functions. 
B. Fritzsche, B. Kirstein, I.Ya. Roitberg, A.L. Sakhnovich
math.SP cs.SY math.CA math.OC