Section RClo.
Inductive rclo5 (clo: rel->rel) (r: rel): rel :=
| rclo5_base
x0 x1 x2 x3 x4
(IN: r x0 x1 x2 x3 x4):
@rclo5 clo r x0 x1 x2 x3 x4
| rclo5_clo'
r' x0 x1 x2 x3 x4
(LE: r' <5= rclo5 clo r)
(IN: clo r' x0 x1 x2 x3 x4):
@rclo5 clo r x0 x1 x2 x3 x4
.

Lemma rclo5_compose clo r:
rclo5 (rclo5 clo) r <5= rclo5 clo r.