摘要: \[ \left| \bigcup_{i=1}^n S_j\right|=\sum_{m=1}^n(-1)^{m+1} \left| \sum_{a_i<a_{i+1}}\bigcap_{i=1}^m S_{a_i} \right| \] \[ \left| \bigcap_{i=1}^n S_i 阅读全文
posted @ 2022-06-12 14:22 Kzos_017 阅读(91) 评论(0) 推荐(0) 编辑