proposition: Lemma ex_fc (P : cmodel -> Prop) : (exists M : fmodel, P M) -> (exists M : cmodel, P M).
proof: Proof. move => [M ?]. by exists M. Qed.
imports: Lia mathcomp.ssreflect.ssreflect mathcomp(all_ssreflect) CompDecModal.libs(edone bcase fset base modular_hilbert sltype) CompDecModal.K(K_def demo)