Section Companion.
Variable gf: rel -> rel.
Hypothesis gf_mon: monotone5 gf.
Inductive cpn5 (r: rel) x0 x1 x2 x3 x4 : Prop :=
| cpn5_intro
clo
(COM: compatible5 gf clo)
(CLO: clo r x0 x1 x2 x3 x4)
.

Lemma cpn5_step r:
gf (cpn5 r) <5= cpn5 r.