The Cohomology of the Complex of G-Invariant Forms onG -Manifolds. II

The cohomology of G-manifolds of the type M=P×_K(G/H), where G is a reductive Lie group, H and N are its closed subgroups, H is a normal subgroup of N, K=N/H, and P is a smooth principal K-bundle, are considered. In the case when the Lie algebras of H and N are reductive, the differential graded algebra C(M) introduced in the previous paper with the same title and having the same minimal model as one of the algebra of G-invariant forms on M is investigated. Moreover, the main theorem on the cohomology algebra of C(M) is proved under weaker conditions than those of the previous paper.