proposition: Lemma GE_prop7 E s : GT E s -> GL E s -> GU E s -> inc (un E s) E /\ unit E s (un E s).
proof: Proof. move => ha hb hc. by case:(select_pr (GE_prop5 ha hb hc) (@GE_prop6 E s)). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)