fact: Axiom disjoint_nil_1 : forall A B (E : list (atom*B)), disjoint (@nil (atom*A)) E.
imports: Coq.FSets.FSets Coq.Lists.List Coq.Logic.Decidable Metalib.CoqFSetDecide Metalib.CoqListFacts Metalib.AssocList Metalib.MetatheoryAtom Metalib.LibTactics