| 释义 |
contrapositive The contrapositive of an implication p ⇒ q is the implication ¬q ⇒ ¬p. An implication and its contrapositive are logically equivalent, so that one is true if and only if the other is. For example, the theorem that if n2 is odd then n is odd could be proved by showing instead that if n is even then n2 is even.
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