proposition: Lemma existE (T : System) (f g : Formula) (v : nat): ~ In_freeVarSys LNN v T -> ~ In v (freeVarF g) -> SysPrf T (exH v, f)%fol -> SysPrf T (f -> g)%fol -> SysPrf T g.
proof: Proof. apply (existE LNN). Qed.
imports: Coq(Arith Ensembles List) LibHyps(LibHyps) hydras(MoreLibHyps NewNotations)