proposition: Theorem _paco2_mult_strong: forall r, paco2 gf (upaco2 gf r) <2== paco2 gf r.
proof: Proof. intros. apply curry_map2. eapply le1_trans; [| eapply _paco_mult_strong]. apply _paco_mon; intros [] H; apply H. Qed.
imports: Program.Basics Paco(paconotation_internal paco_internal pacotac_internal)