This paper USES the set theory, derivation principles and probability method to give a direct and simple solution to several important combinatorial identities.

组合恒等式在组合数学中占有重要的地位，它有多种证法，运用集合论的观点，求导法则和概率方法对几个重要的组合等式给出了直观简洁的证明。

youdao

This paper USES the set theory, derivation principles and probability method to give a direct and simple solution to several important combinatorial identities.

组合恒等式在组合数学中占有重要的地位，它有多种证法，运用集合论的观点，求导法则和概率方法对几个重要的组合等式给出了直观简洁的证明。

youdao