Quadratic pencil of difference equations: Jost solutions, spectrum, and principal vectors

Abstract

In this paper, a quadratic pencil of Schrödinger type difference operator $L_{\lambda }$ is taken under investigation to give a general perspective on the spectral analysis of non-selfadjoint difference equations of second order. Introducing Jost-type solutions, structural and quantitative properties of spectrum of the operator $L_{\lambda }$ are analyzed and hence, a discrete analog of the theory in Degasperis, (\emph{J.Math.Phys}. 11: 551--567, 1970) and Bairamov et. al, (\emph{Quaest. Math.} 26: 15--30, 2003) is developed. In addition, several analogies are established between difference and $q$-difference cases. Finally, the principal vectors of $L_{\lambda }$ are introduced to lay a groundwork for the spectral expansion. Mathematics Subject Classification (2000): 39A10, 39A12, 39A13

References in corpus (1)

• Representation Theory Approach to the Polynomial Solutions of q - Difference Equations : U_q(sl(3)) and Beyond,