Möbius-invariant harmonic function spaces on the unit disc

Abstract

We investigate and identify Möbius-invariant harmonic function spaces on the unit disc. We derive their fundamental properties and establish connections among various topologies on them. We show that the harmonic Bloch space b∞ is the “maximal” and the Besov space b−21 is the minimal invariant complete seminormed space. There is only one invariant semi-Hilbert space and it is the harmonic Dirichlet space b−22. © 2021, Akadémiai Kiadó, Budapest.