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Archive: December 27, 2020

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.

书脊

这青苔碧瓦堆, 俺曾睡风流觉, 将五十年兴亡看饱.