Definition Lindenbaum_preserves {A: Type} (P: Ensemble A -> Prop): Prop :=
  forall (CA: Countable A) init, P init -> P (LindenbaumConstruction CA init P).Definition Lindenbaum_ensures {A: Type} (P cP: Ensemble A -> Prop): Prop :=
  forall (CA: Countable A) init, P init -> cP (LindenbaumConstruction CA init P).Definition Lindenbaum_constructable {A: Type} (P cP: Ensemble A -> Prop): Prop :=
  forall Phi, P Phi -> exists Psi: sig cP, Included _ Phi (proj1_sig Psi) /\ P (proj1_sig Psi).

Lemma Lindenbaum_ensures_by_conjunct {A: Type}: forall P cP1 cP2: Ensemble A -> Prop, Lindenbaum_ensures P cP1 -> Lindenbaum_ensures P cP2 -> Lindenbaum_ensures P (Intersection _ cP1 cP2).