proposition: Lemma gpaco5_dist_reverse clo r rg: (paco5 gf (rclo5 clo (rg \5/ r)) \5/ rclo5 clo r) <5= gpaco5 gf clo r rg.
proof: Proof. intros. destruct PR; cycle 1. - eapply gpaco5_rclo. apply H. - econstructor. apply rclo5_base. left. revert x0 x1 x2 x3 x4 H. pcofix CIH; intros. _punfold H0; [|apply gf_mon]. pstep. eapply gf_mon. apply H0. intros. destruct PR. + apply rclo5_base. right. apply CIH, H. + eapply rclo5_mon. apply H. intros. right. apply CIH0. apply PR. Qed.
imports: Program.Basics Paco(paco5 pacotac)