Hint Resolve stack_enum form_discrete.
Definition UA :=
~ enumerable (compl BPCP).

(* Specifications: *)
Corollary valid_red :
BPCP ⪯ @valid frag.
Corollary valid_undec :
UA -> ~ decidable (@valid frag).
Corollary valid_unenum :
UA -> ~ enumerable (compl (@valid frag)).
Corollary prv_red :
BPCP ⪯ @prv intu frag nil.
Corollary prv_undec :
UA -> ~ decidable (@prv intu frag nil).
Corollary prv_unenum :
UA -> ~ enumerable (compl (@prv intu frag nil)).
Corollary satis_red :
compl BPCP ⪯ @satis full.
Corollary satis_undec :
UA -> ~ decidable (@satis full).
Corollary satis_enum :
UA -> ~ enumerable (@satis full).