+type meta_kind = [ `IsSort | `IsType | `IsTerm ]
+val kind_of_meta: NCic.meta_attrs -> meta_kind
+val set_kind: meta_kind -> NCic.meta_attrs -> NCic.meta_attrs
+val replace_in_metasenv:
+ int -> (NCic.conjecture -> NCic.conjecture) -> NCic.metasenv -> NCic.metasenv
+val max_kind: meta_kind -> meta_kind -> meta_kind
+
+module NCicHash : Hashtbl.S with type key = NCic.term
+
+val mk_appl : NCic.term -> NCic.term list -> NCic.term
+
+(* the context is needed only to honour Barendregt's naming convention *)
+val apply_subst : NCic.substitution -> NCic.context -> NCic.term -> NCic.term
+val apply_subst_metasenv : NCic.substitution -> NCic.metasenv -> NCic.metasenv