contraposition
/ˌkɒntrəpəˈzɪʃən/noun
mass noun
- Logic conversion of a proposition from all A is B to all not-B is not-A【逻】换质位法（如将命题all A is B 换成all not-B is not-A）。
派生词
contrapositive
adjective & noun词源
mid 16th cent.: from late Latin contrapositio（n-）, from the verb contraponere, from contra- 'against' + ponere 'to place'.