Instance paco3_inst  T0 T1 T2 (gf : rel3 T0 T1 T2->_) r x0 x1 x2 : paco_class (paco3 gf r x0 x1 x2) :=
{ pacoacc    := paco3_acc gf;
  pacomult   := paco3_mult gf;
  pacofold   := paco3_fold gf;
  pacounfold := paco3_unfold gf }.Definition monotone3_2 T0 T1 T2 (gf: rel3 T0 T1 T2 -> rel3 T0 T1 T2 -> rel3 T0 T1 T2) :=
  forall x0 x1 x2 r_0 r_1 r'_0 r'_1 (IN: gf r_0 r_1 x0 x1 x2) (LE_0: r_0 <3= r'_0)(LE_1: r_1 <3= r'_1), gf r'_0 r'_1 x0 x1 x2.

Theorem paco3_2_1_acc: forall l r_0 r_1 (OBG: forall rr (INC: r_1 <3= rr) (CIH: l <_paco_3= rr), l <_paco_3= paco3_2_1 gf_0 gf_1 r_0 rr), l <3= paco3_2_1 gf_0 gf_1 r_0 r_1.