摘要
选取一个非空集合X作为全集，2^X对交，并，差，补四种运算作成一个代数系统，文中给出了这四种运算的几个极小完备集。
Take a nonempty set X as the universal set. Then the power set 2X of X forms an algebraic system together with four operations: intersection, union,differece and complement,This paper gives several minimal complete sets with above four operations.
