  A role of reducible connections in Non-Abelian Seiberg-Witten invariants is
analyzed with massless Topological QCD where monopole is extended to
non-Abelian groups version. By giving small external fields, we found that
vacuum expectation value can be separated into a part from Donaldson theory, a
part from Abelian Monopole theory and a part from non-Abelian monopole theory.
As a by-product, we find identities of U(1) topological invariants. In our
proof, the duality relation and Higgs mechanism are not necessary.
