proposition: Lemma Req_RC C D : D \in Req C -> R C `<=` D.
proof: Proof. rewrite !inE. case/predU1P => [->//|/fimsetP [s _ ->]] //. exact: subxx. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base sltype) CompDecModal.CTL(CTL_def dags)