## Abstract Within the framework of the multiple Nevanlinna–Pick matrix interpolation and its related matrix moment problem, we study the rank of block moment matrices of various kinds, generalized block Pick matrices and generalized block Loewner matrices, as well as their Potapov modifications, g
On Representations of Matrix Valued Nevanlinna Functions by u - Resolvents
✍ Scribed by Michael Kaltenbäck; Harald Woracek
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 662 KB
- Volume
- 205
- Category
- Article
- ISSN
- 0025-584X
No coin nor oath required. For personal study only.
✦ Synopsis
We show that every matrix valued generalized Nevanlinna function can be represented w a u-resolvent of a certain selfadjoint relation acting in a Pontryagin space. The negative index of this Pontryagin space may be larger than the number of negative squares of the given function.
The minimal index of negative squares which is needed to obtain such a representation is determined.
In the case of scalar functions, the results presented give rise to some new classes of generalized Nevanlinna functions.
📜 SIMILAR VOLUMES
## Abstract Let __D__ be a unit disk and__M__ be an open arc of the unit circle whose Lebesgue measure satisfies 0 < __l__ (__M__) < 2__π__. Our first result characterizes the restriction of the holomorphic functions __f__ ∈ ℋ︁(__D__), which are in the Hardy class ℋ︁^1^ near the arc__M__ and are de