+(*
+ returns the universe number (used to save it do xml)
+*)
+val univno: universe -> int
+
+ (** re-hash-cons URIs contained in the given universe so that phisicaly
+ * equality could be enforced. Mainly used by
+ * CicEnvironment.restore_from_channel *)
+val recons_graph: universe_graph -> universe_graph
+
+ (** re-hash-cons a single universe *)
+val recons_univ: universe -> universe
+
+ (** consistency chek that should be done before committin the graph to the
+ * cache *)
+val assert_univs_have_uri: universe_graph -> universe list-> unit
+
+ (** asserts the universe is named *)
+val assert_univ: universe -> unit
+
+val compare: universe -> universe -> int
+val eq: universe -> universe -> bool
+