fact: Definition subcover {X : Type} (FS F : Family X) : Prop := Included FS F /\ Included (FamilyUnion F) (FamilyUnion FS).
imports: Coq(ClassicalChoice Description Program.Subset) ZornsLemma(Classical_Wf DecidableDec FiniteIntersections InfiniteTypes) Coq(RelationClasses)