Rule of Transposition/Formulation 2/Forward Implication/Proof

Theorem

 * $\vdash \left({p \implies q}\right) \implies \left({\neg q \implies \neg p}\right)$

Proof

 * align="right" | 3 ||
 * align="right" | 1, 2
 * $\neg p$
 * MTT
 * 1, 2
 * 1, 2