ON THE CARATHEODORY TYPE PROBLEM OF KREIN,M.G. AND LANGER,H

We characterize the solvability of the Caratheodory type problem raise d by M.G. Krein and H. Langer in 1997 by using a generalized version o f the commutant lifting theorem and coefficient characterizations of t he functions in a generalized Schur class. In connection with the latt er, we also answer a question on the Schur algorithm in a generalized Schur class of operator valued functions. (C) Academie des Sciences/El sevier, Paris