Regular Factorization of the Scalar Characteristic Function

It is known that regular factorizations of the characteristic function of an operator describe its invariant subspaces. The case of a scalar characteristic function is considered. Some examples are given. The factorizations describing all chains of invariant subspaces containing a given subspace L are constructed by the factorization describing L. A representation of the regular factorization of a function is obtained in terms of factorizations of its inner and outer parts. Bibliography: 9 titles.