Adjoint of some composition operators on the Dirichlet and Bergman spaces

Abstract

Let $\varphi$ be a holomorphic self-map of the unit disk $\mathbb{U}:=\{z\in \mathbb{C}: |z| < 1\}$, and the composition operator with symbol $\varphi$ is defined by $C_\varphi f=f \circ \varphi.$ In this paper we present formula for the adjoint of composition operators in some Hilbert spaces of analytic functions, in the case that $\varphi$ is a finite Blaschke product or a rational univalent holomorphic self-map of the unit disk $\mathbb{U}$.