proposition: Fact dual_leEmeet (x y : L^d) : (x <= y) = (x `|` y == x).
proof: Proof. by rewrite [LHS]leEjoin joinC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)