simpl in |- *.
unfold union in |- *.
apply union_sound.
apply beta_sound; auto with arith pts.
simpl in |- *.
apply cumul_inv_prod.
exact ecc_is_subtype_dec.
apply delta_sound.
Qed.

(* Construction du type-checker *)
Theorem ecc_algorithms : PTS_TC _ ecc_pts.
Proof
full_cts_type_checker srt_ecc ecc ecc_is_subtype_dec ecc_is_norm_sound.