Multipoint Selfadjoint Quasi-Differential Operators For First Order

Abstract

In the present paper, the aim is to described all selfadjoint extensions of the minimal operator generated by Örst order linear symmetric multipoint quasi-di§erential operator expression in the direct sum of weighted Hilbert spaces of vector-functions deÖned at the semi-inÖnite intervals by using the Calkin-Gorbachuk method. We have also examine the structure of the spectrum of such extensions.