proposition: Lemma gpaco2_dist_reverse clo r rg: (paco2 gf (rclo2 clo (rg \2/ r)) \2/ rclo2 clo r) <2= gpaco2 gf clo r rg.
proof: Proof. intros. destruct PR; cycle 1. - eapply gpaco2_rclo. apply H. - econstructor. apply rclo2_base. left. revert x0 x1 H. pcofix CIH; intros. _punfold H0; [|apply gf_mon]. pstep. eapply gf_mon. apply H0. intros. destruct PR. + apply rclo2_base. right. apply CIH, H. + eapply rclo2_mon. apply H. intros. right. apply CIH0. apply PR. Qed.
imports: Program.Basics Paco(paco2 pacotac)