proposition: Lemma plain_soundness C : gen (C,aVoid) -> prv (~~: [af C]).
proof: Proof. move/hilbert_soundness => /= H. Intro. ApplyH H. by drop. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert sltype) CompDecModal.CTL(CTL_def gen_def hilbert hilbert_hist)