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