We consider contractive homomorphisms of a planar algebra A(Ω) over a finitely connected bounded domain Ω ⊆ C and ask if they are necessarily completely contractive. We show that a homomorphism ρ :… (More)

Let D denote the open unit disk in C centered at 0 . Let H∞ R denote the set of all bounded and holomorphic functions defined in D that also satisfy f (z) = f (z) for all z ∈ D . It is shown that H∞… (More)

Let E , E∗ be Hilbert spaces. Given a Hilbert space H of holomorphic functions in a domain Ω in C, consider the multiplier space MH(E , E∗). It is shown that for “nice enough” H, the following… (More)

A version of Henrici's classical perturbation theorem for eigenvalues of matrices is obtained for joint spectra of commuting tuples of matrices. The approach involves Clifford algebra techniques… (More)