(1) Departamento de Matemáticas, Universidad Autónoma de Madrid, 28049 Madrid, Spain
Abstract:
A well known lemma attributed to Coburn states that a Toeplitz operator with non-trivial kernel acting on the Hardy space must have dense range. We show that the range of a non-zero Toeplitz operator with non-trivial kernel must contain all polynomials and state this in a precise form.
