proposition: Lemma setKUC B A : A :&: (A :|: B) = A.
proof: Proof. by rewrite setUC setKU. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)