Hint Rewrite <- @MakeSequentCalculus_IntuitionisticPropositionalLogic using (instantiate_must_succeed; apply Typeclass_Rewrite_I): AddSC.
Section DerivableRulesFromAxiomatization1.
Context {L: Language}
{minL: MinimunLanguage L}
{pL: PropositionalLanguage L}
{Gamma: ProofTheory L}
{minAX: MinimunAxiomatization L Gamma}
{ipGamma: IntuitionisticPropositionalLogic L Gamma}.

Lemma contrapositivePP: forall (x y: expr),
|-- (y --> x) --> ~~ x --> ~~ y.