+val check_and_add_obj: NCic.obj -> unit
+
+val get_relevance: NReference.reference -> bool list
+
+val type0: NCic.universe
+val get_universes: unit -> NCic.universe list
+val is_declared: NCic.universe -> bool
+val max: NCic.universe -> NCic.universe -> NCic.universe
+(* universe_* raise BadConstraints if the second arg. is an inferred universe *)
+val universe_eq: NCic.universe -> NCic.universe -> bool
+val universe_leq: NCic.universe -> NCic.universe -> bool
+(* add_constraint raise BadConstraint in case of universe inconsistency
+ or if the second argument is an inferred universe
+ true -> strict check (<); false -> loose check (<=)
+*)
+val add_constraint: bool -> NCic.universe -> NCic.universe -> unit
+val sup : NCic.universe -> NCic.universe option
+val pp_constraints: unit -> string
+