proposition: Lemma disjoint_one_1 : forall A B (x : X.t) (a : A) (F : list (X.t*B)), disjoint (x ~ a) F -> ~ In x (dom F).
proof: Proof. unfold disjoint. simpl. 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