Mansfield's Imprimitivity Theorem for Arbitrary Closed Subgroups

Let δ be a nondegenerate coaction of G on a C∗-algebra B, and let H be a closed subgroup of G. The dual action δ̂ : H → Aut(B×δ G) is proper and saturated in the sense of Rieffel, and the generalised fixed-point algebra is the crossed product of B by the homogeneous space G/H . The resulting Morita equivalence is a version of Mansfield’s imprimitivity theorem which requires neither amenability nor normality of H .