On the Jordan structure of the spectral-zero dynamics in multivariable analytic interpolation

The parametrization of solutions to scalar interpolation problems with a degree constraint relies on the concept of spectral-zeros - these are the poles of the inverse of a corresponding spectral factor. In fact, under a certain degree constraint, the spectral-zeros are free (modulo a stability requirement) and parameterize all solutions. The subject of this paper is the multivariable analog of a Nehari-like analytic interpolation with a degree constraint. Our main result is based on Rosenbrock¿s pole assignability theorem and addresses the freedom in assigning the Jordan structure of the spectral-zero dynamics.