proposition: Lemma not_andb_negb_iff {a b : bool} : (is_true a -> is_true b) <-> ~is_true (a && negb b).
proof: Proof. destruct a, b; simpl; intuition. Qed.
imports: Coq.Strings.String Coq.Strings.Ascii Coq.Arith.Arith Coq.ZArith.BinInt Coq.NArith.BinNat Coq.Bool.Bool Coq.Classes.Morphisms Fiat.Common.Coq__8_4__8_5__Compat