By constructing certain maps, this note completes the answer of the question： For which closed orientable 3-manifold N, is the set of mapping degrees D（M, N） finite for any closed orientable 3-manifold M？
基金The third author is partially supported by National Natural Science Foundation of China （Grant No. 10631060） and Ph.D. grant of the Ministry of Education of China （Grant No. 5171042-055）
文摘By constructing certain maps, this note completes the answer of the question： For which closed orientable 3-manifold N, is the set of mapping degrees D（M, N） finite for any closed orientable 3-manifold M？
