Definition monotone0 (gf: rel0 -> rel0) :=
  forall r r' (IN: gf r) (LE: r <0= r'), gf r'.

(* Specifications: *)
Theorem paco0_acc: forall l r (OBG: forall rr (INC: r <0= rr) (CIH: l <_paco_0= rr), l <_paco_0= paco0 gf rr), l <0= paco0 gf r.
Theorem paco0_mon: monotone0 (paco0 gf).
Theorem paco0_mult_strong: forall r, paco0 gf (upaco0 gf r) <0= paco0 gf r.