con.tra.pos.i.tive
n.Logic （名词）【逻辑学】 A proposition derived by negating and permuting the terms of another, equivalent proposition; for example,All not-Y is not-X is the contrapositive of All X is Y. 质位变换命题：由否定和置换另一等价命题的项而得到的命题；例如，.所有的非Y是非X. 是 .所有的X是Y. 的质位变换命题
