Notions of Julia and defect operators are used as a foundation for a theory of matrix
extension and commutant lifting problems for contraction operators on Kreĭn spaces. The …

This modern introduction to operator theory on spaces with indefinite inner product
discusses the geometry and the spectral theory of linear operators on these spaces, the …

The approach, developed in [14], of extrapolation problems in the theory functions by means
of lifting of commutants makes natural to consider prob of lifting of operators with control over …

This work represents a continuation of our investigations [3, 10, 111, dealing with lifting of
operators acting in spaces with indelinite metric and with control over the negative signature …

The well-known results of MG Kreĭn concerning the description of selfadjoint contractive
extensions of a hermitian contraction T_1 T 1 and the characterization of all nonnegative …

A construction is made of a unitary linear system whose transfer function is a given power
series B (z) with operator coefficients such that multiplication by B (z) is an everywhere …

A Construction of Krein Spaces of Analytic Functions Page 1 JOURNAL OF FUNCTIONAL
ANALYSIS 98, 141 (1991) A Construction of Krein Spaces of Analytic Functions LOUIS DE …

Le théorème de dilatation des commutants d'opérateurs ([26],[27],[28]; voir aussi [23]) décrit
certaines extensions d'une contraction donnée entre deux espaces de Hilbert. Plus …

Abstract If $ B $($ z $) is a power series with operator coefficients such that multiplication by
$ B $($ z $) is an everywhere defined transformation in ${\cal C} $(z), then a unique Krein …

A generalization of the well-known results of MG Kreĭn on the description of the self-adjoint
contractive extension of a Hermitian contraction is obtained. This generalization concerns …