Burnside和Polya

Burnside: https://en.wikipedia.org/wiki/Burnside%27s_lemma

Polya: https://en.wikipedia.org/wiki/P%C3%B3lya_enumeration_theorem

Polya是Burnside一种特殊推定, 例题就几个, 都是染色类问题. 个人觉得难点在于如何准确归纳和构建置换.