Spectral properties of a non selfadjoint system of differential equations with a spectral parameter in the boundary condition
Author
Kir, Esra
Bascanbaz-Tunca, Gülen
Yanik, Canan
Full text
https://www.revistaproyecciones.cl/index.php/proyecciones/article/view/147610.4067/10.4067/S0716-09172005000100005
Abstract
In this paper we investigated the spectrum of the operator L(?) generated in Hilbert Space of vector-valued functions L2 (R+, C2) by the system iy0 1 + q1 (x) y2 = ?y1, ?iy0 2 + q2 (x) y1 = ?y2 (0.1) , x ?R+ := [0,?), and the spectral parameter- dependent boundary condition (a1? + b1) y2 (0, ?) ? (a2? + b2) y1 (0, ?)=0, where ? is a complex parameter, qi, i = 1, 2 are complex-valued functions ai 6= 0, bi 6= 0, i = 1, 2 are complex constants. Under the condition sup x?R+ {exp ?x |qi (x)|} < ?, i = 1, 2,?> 0, we proved that L(?) has a finite number of eigenvalues and spectral singularities with finite multiplicities. Furthermore we show that the principal functions corresponding to eigenvalues of L(?) belong to the space L2 (R+, {C2) and the principal functions corresponding to spectral singularities belong to a Hilbert space containing L2 (R+, C2).