Section DerivableRulesFromSequentCalculus.
Context {L: Language}
{GammaD: Derivable L}
{bSC: BasicSequentCalculus L GammaD}.
Context {minL: MinimumLanguage L}
{minSC: MinimumSequentCalculus L GammaD}.

Lemma derivable_axiom1: forall (Phi: context) (x y: expr),
Phi |-- x --> y --> x.