Section DerivableRules.
Context {L: Language}
{minL: MinimumLanguage L}
{pL: PropositionalLanguage L}
{Gamma: Provable L}
{minAX: MinimumAxiomatization L Gamma}
{ipAX: IntuitionisticPropositionalLogic L Gamma}.
Definition multi_and (xs: list expr): expr := fold_left andp xs truep.

Lemma multi_and_spec: forall (xs: list expr),
|-- multi_and xs <--> fold_right andp TT xs.