Proof
CR_WHNF_convert_hn srt_v6 v6_sort_dec (beta_delta_rule srt_v6)
(church_rosser_beta_delta srt_v6) whnf.

(* Specifications: *)
Theorem v6_is_subtype_dec : subtype_dec_CTS _ v6.
apply Build_subtype_dec_CTS.