proposition: Lemma FL_cnf s : is_cnf s -> (forall t, t \in FL s -> is_cnf t).
proof: Proof. exact: FL_cnf_mut.1. Qed.
imports: Relations Lia Setoid Morphisms mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert sltype rewrite_inequality fset_tac)