Generalized resolvents of symmetric operators
The Krein formula for generalized resolvents is one of the highlights of the theory of extensions of symmetric operators in Hilbert spaces. In the present paper, the authors give another more general version of such a formula for generalized \(U\)-resolvents of the isometric operator \(V\). Each boundary triple \(\Pi\) of \(\{V,V^{-1}\}\) generates the formula for generalized resolvents, and its parameters can be expressed in terms of the boundary operators. Now the Schur class of contractive operator-valued functions in the unit disk comes in. Note that there is a misprint in the title of the English version of the paper: ``isometric'' should be written rather than ``symmetric''.
scientific article; zbMATH DE number 2115584