intros.
inversion_clear H.
Inversion_typ H0.
left with s1; trivial with arith pts.
Qed.

(* Specifications: *)
Theorem wf_type_prod_r :
forall (e : env) (A B : term),
wf_type e (Prod A B) -> wf_type (Ax A :: e) B.
Theorem wf_type_prod_r :
forall (e : env) (A B : term),
wf_type e (Prod A B) -> wf_type (Ax A :: e) B.