Weakly and strongly outer functions on the bidisc
The role of the outer functions in the Nevanlinna and Hardy classes is well-known. In this paper the strongly outer and weakly outer functions in these classes are defined. It is shown that many results of the classical one-variable theory have multivariate analogues. Among these are Beurling's theorem, the Riesz factorisation theorem and Szegö's infimum.
scientific article; zbMATH DE number 63015