A note on the spectral singularities of non-selfadjoint matrix-valued difference operators

Let L denote the non-selfadjoint operator generated in ℓ 2 ( N , E ) by the matrix difference expression ( ℓ y ) n = A n − 1 y n − 1 + B n y n + A n y n + 1 , n ∈ N , and the boundary condition y 0 = 0 . In this paper we investigate the Jost solution, the continuous spectrum, the eigenvalues and the spectral singularities of L .