Basis Property of the System of Root Functions of a Classical Spectral Problem with a Multiple Eigenvalue
N. Yu. Kapustin · Differential Equations · 2018
The problem of describing the biorthogonal system of a classical system of root functions is considered for a loaded string problem with a multiple eigenvalue. The basis property of selected complete and minimal subsystems of the system of root functions in the presence of one or two associated functions is studied.