On time dependent orthogonal polynomials on the unit circle
Two index formulas for operators defined by infinite band matrices are proved. These results may be interpreted as a generalization of the classical theorem of M. G. Krein for orthogonal polynomials. The proofs are based on dichotomy and nonstationary inertia theory.
English version (Springer): Ukrainian Mathematical Journal 46 (1994), no. 1-2, pp 15-33.
Citation Example: Ben-Artzi A., Gohberg I. C. On time dependent orthogonal polynomials on the unit circle // Ukr. Mat. Zh. - 1994. - 46, № 1-2. - pp. 18–36.