Adjoint operator of Bergman projection and Besov space B₁

The main result of this paper is related to finding two-sided bounds of norm for the adjoint operator $P^{\ast}$ of the Bergman projection $P,$ where $P$ denotes the Bergman projection wich maps $L^{1}(D,d\lambda(z))$ onto the Besov space $B_{1}.$ Here $d\lambda(z)$ is the M\"obius invariant measure ${(1-|z|^2)^{-2}}{dA(z)}$. It is shown that $2\leq\| P^{\ast}\|\leq 4.$