proposition: Lemma axAUf s t : prv (s ---> fAX (fAU s t) ---> fAU s t).
proof: Proof. rewrite -> axAUeq at 2. do 2 Intro. ApplyH axOIr. ApplyH axAI. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert) CompDecModal.CTL(CTL_def hilbert)