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