Pascal Lefevre (University Artois)
Composition operators on Hardy space
The topic of the talk is composition operators $C_\phi: f\to f\circ\phi$, where the symbol $\phi$ is an analytic function from the open unit disc of the complex plane into itself. We restrict our attention to the case of composition operators acting on Hardy spaces $H^p$. We shall give a (non exhaustive!) overview of old and recent results, as well as open questions around that subject. We shall focus on the membership of various ideal operators.