Module pure_typable_intro_prenex_aux.

Lemma pure_typing_trace_poly_typeE {s ns Gamma t n}:
is_simple s ->
allfv_poly_type (gt (length ns)) s ->
pure_typing
((map (fun x => poly_var (n + x)) ns) ++ poly_abba :: Gamma)
(trace_poly_type (length ns) s) t ->
ren_poly_type (fun x => n + nth x ns 0) s = tidy t.