  We define classical-quantum multiway channels for transmission of classical
information, after recent work by Allahverdyan and Saakian. Bounds on the
capacity region are derived in a uniform way, which are analogous to the
classically known ones, simply replacing Shannon entropy with von Neumann
entropy. For the single receiver case (multiple access channel) the exact
capacity region is determined. These results are applied to the case of noisy
channels, with arbitrary input signal states. A second issue of this work is
the presentation of a calculus of quantum information quantities, based on the
algebraic formulation of quantum theory.
