It is known that, under very general conditions, Blaschke products generate branched covering surfaces of the Riemann sphere. We are presenting here a method of finding fundamental domains of such coverings and we are studying the corresponding groups of covering transformations.
This paper deals with an interpolation problem in the open unit disc $\mathbb D$ of the complex plane. We characterize the sequences in a Stolz angle of $\mathbb D $, verifying that the bounded sequences are interpolated on them by a certain class of not bounded holomorphic functions on $\mathbb D $, but very close to the bounded ones. We prove that these interpolating sequences are also uniformly separated, as in the case of the interpolation by bounded holomorphic functions