proposition: Lemma Rpos s C : s^- \notin R C.
proof: Proof. apply/negP. case/fimsetP => t. rewrite inE andbC. by case (isBoxP t) => // t' ->. Qed.
imports: Relations mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert sltype)