Section DerivableRulesFromSequentCalculus.
Context {L: Language}
{Gamma: ProofTheory L}
{bSC: BasicSequentCalculus L Gamma}.
Context {minL: MinimunLanguage L}
{minSC: MinimunSequentCalculus L Gamma}.

Lemma deduction_impp_elim: forall Phi x y,
Phi |-- impp x y ->
Union _ Phi (Singleton _ x) |-- y.