proposition: Lemma ex9_map_ax : lf_axiom ex9_map_val ex9_quo F.
proof: Proof. move: (chain_equivalence_eq) => [eqv seq]. move => x /ex9_quoP []; rewrite seq; move/ex9G_P =>[pr Qr Pr] _. move: (function_u Qr) => [fu su tu]. rewrite /ex9_map_val; Wtac. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)