Hae
Aineistot 11-14 / 14
On Kreǐn's extension theory of non-negative operators
(Vaasan yliopisto, 2002)
- workingPaper
The famous M.G. Kreın’s extension theory of nonnegative operators is being presented in elementary terms, building on the completion of nonnegative operator blocks. The present treatment includes the refinements to the ...
Q-functions of Hermitian contractions of Krein-Ovcharenko type
(Vaasan yliopisto, 2003)
- workingPaper
Operator valued Q-functions of Krein-Ovcharenko type are introduced. Such functions arise from the extension theory of Hermitian contractive operators A in a Hilbert space H. The definition is related to the investigations ...
Singular perturbations of selfadjoint operators
(Vaasan yliopisto, 2002)
- workingPaper
Singular perturbations as range perturbations in a Pontryagin space
(Vaasan yliopisto, 2003)
- workingPaper