odd molecule

G has a perfect matching if and only if o(G-S)≤|S|for all SV,where o(G-S) denotes the number of odd components of G.

图 G有完美匹配当且仅当对于其顶点集 V的任意子集 S,G-S的奇分支的个数不超过 S中元素的个数 。