Section DerivableRules_multi_impp.
Context {L: Language}
{minL: MinimunLanguage L}
{Gamma: ProofTheory L}
{minAX: MinimunAxiomatization L Gamma}.

Lemma provable_multi_imp_shrink: forall (xs: list expr) (x y: expr), |-- (x --> multi_imp xs (x --> y)) --> multi_imp xs (x --> y).