# contrapositive

A contrapositive statement is statement derived from a conditional by reversing and negating its antecedent and consequent. Thus the contrapositive of the conditional statement ‘if $$A$$ then $$B$$’ is ‘if not $$B$$ then not $$A$$.’ In symbolic logic this is written as $$\neg B \rightarrow \neg A$$.

A conditional and its contrapositive are logically equivalent; each is true precisely when $$B$$ is true or $$A$$ is false.