Théorèmes de factorisation dans les espaces
Our aim is to prove that for any fixed 1/2 < α < 1 there exists a Hilbert space contraction T such that σ(T) = 1 and . This answers Zemánek’s question on the time regularity property.
If ϕ is an analytic self-mapping of the unit disc D and if is the Hardy-Hilbert space on D, the composition operator on is defined by . In this article, we consider which Toeplitz operators satisfy