proposition: Lemma subCs s C : s |` C \in Cs -> s \in F.
proof: Proof. by rewrite !powersetE fsubUset fsub1; bcase. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base sltype) CompDecModal.CTL(CTL_def gen_def)