Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
This paper is devoted to the presentation, within the framework of a coordinate-free model, of two known Sz. Nagy-Foiaş theorems: The first one deals with the correspondence between the invariant subspaces of a contraction T and the regular factorizations of its characteristic function θT, while the second one is the commutant lifting theorem. The proofs are based on a coordinate-free approach to the model. In the first theorem an essential point is the singling out of the role of functional imbeddings and the formulation of a criterion for the existence of an invariant subspace in terms of a functional imbedding of a special form. As far as the commutant lifting theorem is concerned, our approach enables us to give a parametrization of the lifted operators with the aid of one free parameter instead of two dependent ones, as done by Sz.-Nagy and Foiaş.
Язык оригинала | английский |
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Страницы (с-по) | 1951-1962 |
Число страниц | 12 |
Журнал | Journal of Soviet Mathematics |
Том | 61 |
Номер выпуска | 2 |
DOI | |
Состояние | Опубликовано - 1 авг 1992 |
ID: 49880122