proposition: Lemma tref_R2 C s : tref (s^- |` R C) -> tref (fAX s^- |` C).
proof: Proof. by constructor. Qed.
imports: Relations Lia mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert sltype) CompDecModal.Kstar(Kstar_def demo hilbert_ref gen_def)