On the Krein-Langer integral representation of generalized Nevanlinna functions

Main Article Content

James L. Rovnyak
Lev A. Sakhnovich


The Krein-Langer integral representation of a matrix-valued generalized Nevanlinna function arises in problems of spectral theory and interpolation. A version of this formula which is suitable for such problems, and a corresponding Stieltjes inversion formula, are derived. Some classes of generalized Nevanlinna functions which are defined in terms of behavior at infinity are characterized in terms of their integral representations. 

Article Details