Section DerivableRulesFromAxiomatization1.
Context {L: Language}
{minL: MinimumLanguage L}
{pL: PropositionalLanguage L}
{Gamma: Provable L}
{minAX: MinimumAxiomatization L Gamma}
{ipGamma: IntuitionisticPropositionalLogic L Gamma}.

Lemma solve_impp_elim_left: forall x y: expr,
|-- y -> |-- x --> y.