Section Compatibility.
Variable gf: rel -> rel.
Hypothesis gf_mon: monotone3 gf.
Structure compatible3 (clo: rel -> rel) : Prop :=
compat3_intro {
compat3_mon: monotone3 clo;
compat3_compat : forall r,
clo (gf r) <3= gf (clo r);
}.
Structure wcompatible3 clo : Prop :=
wcompat3_intro {
wcompat3_mon: monotone3 clo;
wcompat3_wcompat : forall r,
clo (gf r) <3= gf (gupaco3 gf clo r);
}.

Lemma wcompat3_union clo1 clo2
(WCMP1: wcompatible3 clo1)
(WCMP2: wcompatible3 clo2):
wcompatible3 (clo1 \4/ clo2).