proposition: Theorem PCPb_entailment_ZFeq' : PCPb ⪯ entailment_ZFeq'.
proof: Proof. exists solvable. intros B. split; intros H. - eapply PCP_ZFD, soundness in H. intros D M rho H'. apply H, H'. - now apply PCP_ZFeq'; try apply intensional_model. Qed.
imports: Undecidability.Synthetic.Definitions Undecidability.Synthetic.Undecidability Undecidability.FOL(Semantics.Tarski.FullFacts Semantics.Tarski.FullSoundness) Undecidability.FOL.Sets.Models(Aczel_CE Aczel_TD ZF_model HF_model) Undecidability.FOL.Reductions(ZF_to_HF PCPb_to_HF PCPb_to_HFD PCPb_to_ZFeq PCPb_to_ZF PCPb_to_ZFD) Undecidability.FOL.Sets.ZF Undecidability.FOL.ZF Undecidability.PCP(PCP PCP_undec Util.PCP_facts Reductions.PCPb_iff_dPCPb)