proposition: Lemma gpaco4_unfold clo r rg: gpaco4 clo r rg <4= rclo4 clo (gf (gupaco4 clo (rg \4/ r)) \4/ r).
proof: Proof. intros. destruct PR. eapply rclo4_mon. apply IN. intros. destruct PR; cycle 1. right; apply H. left. _punfold H; [|apply gpaco4_def_mon]. eapply gf_mon. apply H. intros. econstructor. eapply rclo4_mon. apply PR. intros. destruct PR0; cycle 1. right. apply H0. left. eapply paco4_mon. apply H0. intros. left. apply PR0. Qed.
imports: Program.Basics Paco(paco4 pacotac)