Definition:Conjugate Statements

Definition
Let $p$ and $q$ be statements.

The conditional statement:
 * $p \implies q$

its inverse:
 * $\lnot p \implies \lnot q$

its converse:
 * $q \implies p$

and its contrapositive:
 * $\lnot q \implies \lnot p$

are all conjugate statements.