14 papers
Characteristic function of M. S. Livšic and triangular models of bounded linear operators
Vladimir K. Dubovoy, Bernd Kirstein, Conrad Mädler +1
This paper is dedicated to the introduction in a circle of ideas and methods, which are connected with the notion of characteristic function of a non-selfadjoint operator. We start…
Characteristic Function, Schur Parameters and Pseudocontinuation of Schur functions
Vladimir K. Dubovoy, Bernd Fritzsche, Bernd Kirstein +2
In [19] there is an approach to the investigation of the pseudocontinuability of Schur functions in terms of Schur parameters. In particular, there was obtained a criterion for the…
Characteristic Function, Schur Interpolation Problem and Darlington Synthesis
Sergey S. Boiko, Vladimir K. Dubovoy, Bernd Fritzsche +3
In this paper we would like to show the interrelation between the different mathematical theories concerning the Schur interpolation problem, contractions in Hilbert spaces, pseudo…
block representations of the Moore-Penrose inverse and orthogonal projection matrices
Bernd Fritzsche, Conrad Mädler
In this paper, new block representations of Moore-Penrose inverses for arbitrary complex block matrices are given. The approach is based on block representations of orth…
A Potapov-type approach to a truncated matricial Stieltjes-type power moment problem
B. Fritzsche, B. Kirstein, C. Mädler +1
The paper gives a parametrization of the solution set of a matricial Stieltjes-type truncated power moment problem in the non-degenerate and degenerate cases. The key role plays th…
An Application of the Schur Complement to Truncated Matricial Power Moment Problems
Bernd Fritzsche, Bernd Kirstein, Conrad Mädler
The main goal of this paper is to reconsider a phenomenon which was treated in earlier work of the authors' on several truncated matricial moment problems. Using a special kind of…