simpl in |- *.
apply union_sound.
apply beta_sound; auto with arith pts.
simpl in |- *.
apply cumul_inv_prod.
exact v6_is_subtype_dec.
apply delta_sound.
Qed.
(* L'axiome:  ECC est fortement normalisant *)
Axiom
v6_normalise :
forall (e : env_v6) (t T : trm_v6), typ_v6 e t T -> v6_sn e t.

Lemma v6_is_norm_sound : norm_sound_CTS _ v6.