Open 3-manifolds which are connected sums of closed ones

Abstract: We consider open, oriented 3-manifolds which are infinite connected sums of closed 3-manifolds. We introduce some topological invariants for these manifolds and obtain a classification in the case where there are only finitely many summands up to diffeomorphism. This result encompasses both the Kneser-Milnor Prime Decomposition Theorem for closed 3-manifolds and the Ker{\'e}kj{\'a}rt{\'o}-Richards classification theorem for open surfaces.