© 1990 by London Mathematical Society
Natural Function Spaces
School of Mathematics 39 Trinity College, Dublin 2
In this paper we propose a criterion for naturality of a norm on a space of analytic functions defined on the unit disc D in the complex plane C, a criterion which seems to be satisfied in the usual examples of function spaces. For Möbius-invariant function spaces we can recover some results of Arazy, Fisher and Peetre [5, 4], but with fewer assumptions. In particular, we generalise the result of Arazy and Fisher [4] on the uniqueness of the Dirichlet space as a Möbius-invariant semiHilbert space of analytic functions on D.