proposition: Lemma ax_cnfE s : prv (cnf s ---> s).
proof: Proof. rewrite -> ax_cnf. exact: axI. Qed.
imports: Relations Lia Setoid Morphisms mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert sltype rewrite_inequality fset_tac)