proposition: Lemma orE (T : System) (f g h : Formula): SysPrf T (f \/ g)%nt -> SysPrf T (f -> h)%nt -> SysPrf T (g -> h)%nt -> SysPrf T h.
proof: Proof. apply (orE LNT). Qed.
imports: Coq(Arith Ensembles List) hydras.Ackermann(Languages folProof folProp folLogic3)