用划分,求和,再递推的方法给出了四类图完美匹配数目的显式表达式.所给方法可以计算出许多二分图所有完美匹配的数目.
By applying differentiation, summation and re - recursion calculation, several counting formulas of the perfect matchings for four specific types of graphs are given. Many bipartite graphs of the number of all perfect matchings can be calculated by the method presented in this paper.