Corollary paco7_mult: forall r,
  paco7 gf (paco7 gf r) <7= paco7 gf r.

(* Specifications: *)
Theorem paco7_fold: forall r, gf (upaco7 gf r) <7= paco7 gf r.
Theorem paco7_unfold: forall (MON: monotone7 gf) r, paco7 gf r <7= gf (upaco7 gf r).