proposition: Lemma setUidPr A B : reflect (A :|: B = B) (A \subset B).
proof: Proof. by rewrite setUC; apply: setUidPl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop)