The main result isTheorem 4.2 C(ML) = D-(c-1)(n-b1(ML)) (Mc*L ) is a topological invariant of ML, where n is thenumber of components of L, b1 (ML ) is the first Betti number of ML, c*L is the link consisting of c parallel copies of L.

• 定理4.；2 是ML的拓扑不变量，其中n是L的分支数，b_1(M_L)是M_L的一阶Betti数，c~*L是L的c股平行拷贝。