The double commutant property for composition operators
- Miguel Lacruz
- Fernando León Saavedra
- Srdjan Petrovic
- Luis Rodríguez Piazza
ISSN: 0010-0757
Año de publicación: 2019
Volumen: 70
Fascículo: 3
Páginas: 501-532
Tipo: Artículo
Otras publicaciones en: Collectanea mathematica
Resumen
We investigate the double commutant property for a composition operator �� , induced on the Hardy space �2(�) by a linear fractional self-map � of the unit disk �. Our main result is that this property always holds, except when � is a hyperbolic automorphism or a parabolic automorphism. Further, we show that, in both of the exceptional cases, {��}′′ is the closure of the algebra generated by �� and �−1�, either in the weak operator topology, if � is a hyperbolic automorphism, or surprisingly, in the uniform operator topology, if � is a parabolic automorphism. Finally, for each type of a linear fractional mapping, we settle the question when any of the algebras involved are equal.