A MINIMUM RADUIS OF PERTURBED MULTIPLE EIGENVALUES OF AN INTERVAL MATRIX

This paper is concerned with computing bounds for the eigenvalues of an interval matrix with small deviation matrix for the case of semisimple multiple eigenvalues. The approach adopted in this paper, denoted by the interval perturbation method, is a modification of a solution method based on the first-order perturbation theory and interval theory. The bound obtained is in the form of a min-radius of the eigenvalues .clustered around a centre value of the complex plane. The modified algorithm is applied to test matrices with multiple eigenvalues for different matrix dimensions, multiplicities, and width of interval matrix to verify the effectiveness of the interval perturbation method.