proposition: Theorem xm_soundness (xm : XM) s : prv s -> forall (M : ts) (w : M), eval s w.
proof: Proof. exact: xm_soundness. 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)