This paper is concerned with the following question: if a characteristic function satisfies a certain property at the origin, what can be said about its behavior on ...

Let A = (A₁,...,An) and B = (B₁,...,Bn) be row contractions on Hilbert spaces 𝓗₁ and 𝓗₂, respectively, and L be a contraction from D B = ran ¯ D B to D A * = ran ¯ D A * where DB = (I – B*B)1/2 and ...