Generalized Poincar� metric on the operator ball

1984 ◽  
Vol 17 (4) ◽  
pp. 321-323 ◽  
Author(s):  
V. A. Khatskevich
Keyword(s):  
Operator Ball

On an Extension Problem for Contractive Block Hankel Operator Matrices

Analysis ◽  
2005 ◽  
Vol 25 (1) ◽  
Author(s):  
Bernd Fritzsche ◽  
Bernd Hirstein ◽  
Jürgen Lorenz
Keyword(s):  
Hankel Operator ◽  
Hankel Operators ◽  
Linear Operators ◽  
Extension Problem ◽  
Operator Matrices ◽  
Bounded Linear ◽  
Nondegenerate Case ◽  
Operator Version ◽  
Operator Ball ◽  
Operator Extension

AbstractThe paper deals with an operator extension problem for contractive block Hankel operators which arose in the context of the operator version of the classical Nehari interpolation problem. V.M. Adamjan, D.Z. Arov, and M.G. Krein [5] obtained that the solution set of this operator extension problem is an operator ball. Hereby, they constructed the parameters of this operator ball via a regularization procedure using the corresponding expressions of the first studied nondegenerate case. The main aim of this paper is to derive more explicit formulas for the parameters of this operator ball. Hereby we use Moore-Penrose inverses of bounded linear operators in Hilbert space.

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