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Information × Registration Number 0307U001604, 0106U008147 , R & D reports Title Spectral theory of some classes of singularly perturbed operators popup.stage_title Узагальнені матриці Якобі і збіжність діагональних апро-ксимацій Паде. Head Derkach Volodymyr Oleksandrovich, Registration Date 16-04-2007 Organization Donetsk National University popup.description2 The notion of a boundary relation for a symmetric operator acting in a Hilbert space is introduced. A construction of a coupling of two boundary triplets is presented. Thanks to this one obtains a simple proof of Krein-Naimark formula for generalized resolvents. A simple criterion of M-admissibility of generalized resolvent is found and the hypothesis of Langer-Textorius is proven. A description of Weyl functions of generalized Jacobi matrices is obtained. Inverse problems of Borg type and Hohshtadt-Lieberman type on recovery of generalized Jacobi matrices from their spectral data are solved. For a singular Sturm-Liouville operators with an indefinite weight function new conditions of similarity to a selfadjoint operator are given in terms of the Weyl-Titchmarsh m-function. Product Description popup.authors popup.nrat_date 2020-04-02 Close