Hamilton-圈
G 2
G 3
G 4
完美匹配的交
M 3 ∩ M 4 = ∅
M 2 ∩ M 4 = ∅
M 2 ∩ M 3 = ∅
完美匹配的不交并
M 3 ∪ ˙ M 4
M 2 ∪ ˙ M 4
M 2 ∪ ˙ M 3