Section DerivableRulesFromSequentCalculus1.
Context {L: Language}
{minL: MinimumLanguage L}
{pL: PropositionalLanguage L}
{Gamma: Derivable L}
{bSC: BasicSequentCalculus L Gamma}
{minSC: MinimumSequentCalculus L Gamma}
{ipSC: IntuitionisticPropositionalSequentCalculus L Gamma}.

Lemma derivable_orp_elim: forall (Phi: context) (x y z: expr),
Phi |-- (x --> z) --> (y --> z) --> (x || y --> z).