考虑完全图K4的列表边染色 X X 义4 在点W周围，必须满足 X1≠X4X1-X4≠0 X1≠X5)X1-X5≠0 →(x1-X4)(x1-X5)X4-X5)≠0 X4≠X5→X4-X5≠0考虑完全图 K4的列表边染色 --------------------------------------------------------- 在点 w 周围，必须满足 x1≠x4  x1-x4≠0 x1≠x5  x1-x5≠0  (x1-x4)(x1-x5)(x4-x5) ≠0 x4≠x5  x4-x5≠0