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