This paper characterizes all controllers to a problem of simultaneous robust regulation and robust stabilization, which was left open by Cevik and Schumacher. The characterization is based on a combination of their results, i.e., the controller parameterization of robust regulation with nominal internal stability and the stability margin given by an internally stabilizing controller. The contro...

The generalized Stieltjes–Wigert polynomials depending on parameters 0 ≤ p < 1 and 0 < q < 1 are discussed. By removing the mass at zero of an N-extremal solution concentrated in the zeros of the D-function from the Nevanlinna parametrization, we obtain a discrete measure μM , which is uniquely determined by its moments. We calculate the coefficients of the corresponding orthonormal polynomials...

In this paper we investigate some aspect of the Nevanlinna-Pick and Schur interpolation problem formulated for Schur-functions considered on the right-half plane of C. We consider the well established parametrization of the solution Q = TΘ(S) := (SΘ12 + Θ22)(SΘ11 + Θ21) (see e.g. [2],[6]), where the J-inner function Θ is completely determined by the interpolation data and S is an arbitrary Schu...

Abstract In this article, it is shown that Koebe inner functions and squares of singular Nevanlinna functions, so called atomic density have minimal realizations in reproducing kernel Krein spaces.

The subclasses N (∞) κ of the classes N κ of generalized Nevanlinna functions appear in the context of Pontryagin space models, where they correspond to model relations having a particular spectral behaviour. Applications are found, for instance, in the investigation of differential expressions with singular coefficients. We study representations of N (∞) κ-functions as Cauchy-type integrals in...