1. 求有限集上给定关系的自反、对称和传递闭包。（有两种求解方法，只做一种为A，两种都做为B） 2. 求有限集上等价关系的数目。（有两种求解方法，只做一种为A，两种都做为B） -1. Find a limited set of relations on a given reflexive, symmetric and transitive closure. (There are two solution method, only one is A, both are used as B)