P. Podles, SYMMETRIES OF QUANTUM SPACES - SUBGROUPS AND QUOTIENT-SPACES OF QUANTUM SU(2) AND SO(3) GROUPS, Communications in Mathematical Physics, 170(1), 1995, pp. 1-20
We prove that each action of a compact matrix quantum group on a compa
ct quantum space can be decomposed into irreducible representations of
the group. We give the formula for the corresponding multiplicities i
n the case of the quotient quantum spaces. We describe the subgroups a
nd the quotient spaces of quantum SU(2) and SO(3) groups.