val is_closed : Cic.term -> bool
val is_meta_closed : Cic.term -> bool
val metas_of_term : Cic.term -> (int * Cic.term option list) list
+(* as before but with no duplicates. may avoind some stack overflows *)
+val metas_of_term_set : Cic.term -> (int * Cic.term option list) list
(** @raise Failure "not enough prods" *)
val strip_prods: int -> Cic.term -> Cic.term