proposition: Lemma opredU (S : joinLatticeClosed T) : {in S &, forall u v, u `|` v \in S}.
proof: Proof. exact: opredU. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)