Abstract
In this paper, we investigate a direct and an inverse eigenvalue problem to recover doubly periodic pseudo-Jacobi matrices from three spectra lambda, mu(1), mu(2) and two positive numbers beta*, beta<>. Necessary and sufficient conditions for the existence of solution are given and numerical algorithms, using a modified unsymmetric Lanczos scheme, to reconstruct the matrix from the prescribed data are proposed. Some illustrative numerical examples are presented. The obtained results recover and extend several existing results in the literature.(c) 2021 Elsevier B.V. All rights reserved.
NSTL
Elsevier