The order-preserving doubly mapping on a Boolean algebra equivalents to symmetryoperation;
布尔代数上保序对合映射与对称运算等价；
2
To give better advice on teaching, futher discussion, is made on how to simplify the double integral operation with symmetry, precisely and effectively.
为更好地指导教学，文章还对如何准确、有效地利用对称性简化二重积分的计算作了进一步的探讨。
3
In the end, two building that follow the two principles respectively are to be anatomized, follow three levels of formal operation—taxis, genera and symmetry.