proposition: Lemma disjoint_nil_1 : forall A B (E : list (X.t*B)), disjoint (@nil (X.t*A)) E.
proof: Proof. unfold disjoint. fsetdec. Qed.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Coq.Strings.String String Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.LibTactics Metalib.CoqFSetInterface Coq.Classes.Equivalence Coq.Classes.EquivDec Metalib.CoqEqDec