Electronic Journal of Differential Equations,
Vol. 2013 (2013), No. 231, pp. 1-10.

Title: Selfadjoint extensions of multipoint singular differential operators

Author: Zameddin I. Ismailov (Karadeniz Technical Univ., Trabzon, Turkey)

Abstract:
 This article describes all selfadjoint extensions of the minimal
 operator generated by a linear singular multipoint symmetric
 differential-operator expression for first order in the direct sum
 of Hilbert spaces of vector-functions.
 This description is done in terms of the boundary values, and it uses the
 Everitt-Zettl and the Calkin-Gorbachuk methods.
 Also the structure of the spectrum of these extensions is studied.

Submitted September 19, 2013. Published October 18, 2013.
Math Subject Classifications: 47A10.
Key Words: Everitt-Zettl and Calkin-Gorbachuk methods; singular multipoint;
 differential operators; selfadjoint extension; spectrum