proposition: Lemma axARdef s t : prv (fAR s t <--> ~~: EU (~~: s) (~~: t)).
proof: Proof. rewrite /EU. do ! rewrite -> axDNE. reflexivity. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert) CompDecModal.CTL(CTL_def hilbert)