proposition: Lemma rRegAX s t : prv (s ---> t) -> prv (fAX s ---> fAX t).
proof: Proof. move => H. rewrite -> (axAXdef s), -> (axAXdef t). rule ax_contraNN. apply: rRegEX. by rule ax_contraNN. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert) CompDecModal.CTL(CTL_def hilbert)