Reduction of Representations of SUm+n with respect to the Subgroup SUmSUn

Abstract
A direct and rapid method is described for the reduction of representations of the special unitary group SUm+n with respect to its SUmSUn subgroup. The technique is illustrated by specific reference to the case of SU6 and its SU2SU4 subgroup in the context of the recent extension of Wigner's (SU4) supermultiplet theory into the domain of particle physics. A tabulation of results is given for a slight generalization of this case where reduction is carried out with respect to U1SU2SU4.