Bergman projection and BMO in hyperbolic metric: improvement of classical result.

Abstract

The Bergman projection $P_\alpha$, induced by a standard radial weight, is bounded and onto from $L^\infty$ to the Bloch space $\mathcal{B}$. However, $P_\alpha: L^\infty\to \mathcal{B}$ is not a projection. This fact can be emended via the boundedness of the operator $P_\alpha:\BMO_2(\Delta)\to\mathcal{B}$, where $\BMO_2(\Delta)$ is the space of functions of bounded mean oscillation in the Bergman metric.

We consider the Bergman projection $P_\omega$ and the space $\BMO_{\omega,p}(\Delta)$ of functions of bounded mean oscillation induced by $1<p<\infty$ and a radial weight $\omega\in\mathcal{M}$. Here $\mathcal{M}$ is a wide class of radial weights defined by means of moments of the weight, and it contains the standard and the exponential-type weights. We describe the weights such that $P_\omega:\BMO_{\omega,p}(\Delta)\to\mathcal{B}$ is bounded. They coincide with the weights for which $P_\omega: L^\infty \to \mathcal{B}$ is bounded and onto. This result seems to be new even for the standard radial weights when $p\ne2$.