proposition: Lemma XM_required : (forall s, prv s -> forall (M : ts) (w : M), eval s w) -> XM.
proof: Proof. exact: XM_required. Qed.
imports: mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset modular_hilbert base sltype) CompDecModal.K(K_def demo hilbert_ref gentzen universal_model)