  In Shannon information theory the capacity of a memoryless communication
channel cannot be increased by the use of feedback from receiver to sender. In
this paper the use of classical feedback is shown to provide no increase in the
unassisted classical capacity of a memoryless quantum channel when feedback is
used across non-entangled input states, or when the channel is an
entanglement--breaking channel. This gives a generalization of the Shannon
theory for certain classes of feedback protocols when transmitting through
noisy quantum communication channels.
