Bergman inner functions and m-hypercontractions

We characterize operator-valued Bergman inner functions on the unit ball as functions admitting a suitable transfer function realization. Thus we extend corresponding one-variable results of Olofsson from the case of the unit disc to the unit ball. At the same time we associate with each m-hypercontraction T∈L(H)n a canonical Bergman inner function WT and indicate a possible definition of a characteristic function θT for T.