  Collective rotation channels are a fundamental class of channels in quantum
computing and quantum information theory. The commutant of the noise operators
for such a channel is a C*-algebra which is equal to the set of fixed points
for the channel. Finding the precise spatial structure of the commutant algebra
for a set of noise operators associated with a channel is a core problem in
quantum error prevention. We draw on methods of operator algebras, quantum
mechanics and combinatorics to explicitly determine the structure of the
commutant for the class of collective rotation channels.
