  For any maximal coaction (A, G, delta) and any closed normal subgroup N of G,
there exists an imprimitivity bimodule Y between the full crossed product A x G
x N and A x G/N, together with a compatible coaction delta_Y of G. The
assignment (A, delta) -> (Y, delta_Y) implements a natural equivalence between
the crossed-product functors "x G x N" and "x G/N", in the category whose
objects are maximal coactions of G and whose morphisms are isomorphism classes
of right-Hilbert bimodule coactions of G.
