Instance paco0_inst  (gf : rel0->_) r : paco_class (paco0 gf r) :=
{ pacoacc    := paco0_acc gf;
  pacomult   := paco0_mult gf;
  pacofold   := paco0_fold gf;
  pacounfold := paco0_unfold gf }.Definition monotone0_2 (gf: rel0 -> rel0 -> rel0) :=
  forall r_0 r_1 r'_0 r'_1 (IN: gf r_0 r_1) (LE_0: r_0 <0= r'_0)(LE_1: r_1 <0= r'_1), gf r'_0 r'_1.

Theorem paco0_2_1_acc: forall l r_0 r_1 (OBG: forall rr (INC: r_1 <0= rr) (CIH: l <_paco_0= rr), l <_paco_0= paco0_2_1 gf_0 gf_1 r_0 rr), l <0= paco0_2_1 gf_0 gf_1 r_0 r_1.