try
          let nref = NReference.reference_of_string uri in
           NCic.Const nref
-(*
-         let _,height,_,_,obj = NCicEnvironment.get_checked_obj nuri in
-         let spec =
-          match obj with
-             NCic.Constant (_,_,None,_,_) -> NReference.Decl
-           | NCic.Constant (_,_,Some _,_,_) -> NReference.Def height
-           | NCic.Fixpoint (is_ind,fl,_) ->
-              (* CSC: bug here: name need not be the wanted name
-                 Solution: a real new _reference_ should arrive here *)
-              (match
-                HExtlib.list_index (fun (_,name',_,_,_) -> name=name') fl,is_ind
-               with
-                  None,_ -> assert false
-                | Some (i,(_,_,recno,_,_)),true-> NReference.Fix(i,recno,height)
-                | Some (i,(_,_,_,_,_)),false -> NReference.CoFix i)
-           | NCic.Inductive (inductive,leftno,il,_) ->
-              (match
-                HExtlib.list_index (fun (_,name',_,_) -> name=name') il
-               with
-                  None ->
-                   let cl =
-                    List.concat
-                     (HExtlib.list_mapi (fun (_,_,_,cl) i ->
-                       List.map (fun t -> i,t) cl) il)
-                   in
-                    (match
-                      HExtlib.list_index (fun i,(_,name',_) -> name=name') cl
-                     with
-                        None -> assert false
-                      | Some (j,(i,_)) -> NReference.Con (i,j,leftno))
-                | Some (i,_) -> NReference.Ind (inductive,i,leftno))
-         in
-          NCic.Const (NReference.reference_of_spec nuri spec)
-        with
-         NCicEnvironment.ObjectNotFound _ ->
-*)
         with
          NReference.IllFormedReference _ ->
           let uri = UriManager.uri_of_string uri in
   | DisambiguateTypes.Num instance -> mk_num_alias instance
 ;;
 
+let nlookup_in_library 
+  interactive_user_uri_choice input_or_locate_uri item 
+=
+  match item with
+  | DisambiguateTypes.Id id -> 
+     (try
+       let references = NCicLibrary.resolve id in
+        List.map
+         (fun u -> LexiconAst.Ident_alias (id,NReference.string_of_reference u)
+         ) references @
+        lookup_in_library interactive_user_uri_choice input_or_locate_uri item
+      with
+       NCicLibrary.ObjectNotFound _ ->
+        lookup_in_library interactive_user_uri_choice input_or_locate_uri item)
+  | _ -> lookup_in_library interactive_user_uri_choice input_or_locate_uri item 
+;;
+
   (** @param term not meaningful when context is given *)
 let disambiguate_term expty text prefix_len lexicon_status_ref context metasenv
 term =
         ~aliases:lexicon_status.LexiconEngine.aliases
         ~expty 
         ~universe:(Some lexicon_status.LexiconEngine.multi_aliases)
-        ~lookup_in_library
+        ~lookup_in_library:nlookup_in_library
         ~mk_choice:ncic_mk_choice
         ~mk_implicit
         ~description_of_alias:LexiconAst.description_of_alias
        (try
          (match 
           NCicDisambiguate.disambiguate_obj
-           ~lookup_in_library
+           ~lookup_in_library:nlookup_in_library
            ~description_of_alias:LexiconAst.description_of_alias
            ~mk_choice:ncic_mk_choice
            ~mk_implicit
   let diff, _, _, cic =
    singleton "third"
     (NCicDisambiguate.disambiguate_obj
-      ~lookup_in_library
+      ~lookup_in_library:nlookup_in_library
       ~description_of_alias:LexiconAst.description_of_alias
       ~mk_choice:ncic_mk_choice
       ~mk_implicit
 
 exception ObjectNotFound of string Lazy.t
 
 let storage = ref [];;
-let add_obj u obj = storage := (u,obj)::!storage;;
+
+let aliases = ref [];;
+
+let resolve name =
+ try
+  HExtlib.filter_map
+   (fun (name',nref) -> if name'=name then Some nref else None) !aliases
+ with
+  Not_found -> raise (ObjectNotFound (lazy name))
+;;
+
+let add_obj u obj =
+ storage := (u,obj)::!storage;
+  let _,height,_,_,obj = obj in
+  let references =
+   match obj with
+      NCic.Constant (_,name,None,_,_) ->
+       [name,NReference.reference_of_spec u NReference.Decl]
+    | NCic.Constant (_,name,Some _,_,_) ->
+       [name,NReference.reference_of_spec u (NReference.Def height)]
+    | NCic.Fixpoint (is_ind,fl,_) ->
+       HExtlib.list_mapi
+        (fun (_,name,recno,_,_) i ->
+          if is_ind then
+           name,NReference.reference_of_spec u (NReference.Fix(i,recno,height))
+          else
+           name,NReference.reference_of_spec u (NReference.CoFix i)) fl
+    | NCic.Inductive (inductive,leftno,il,_) ->
+       List.flatten
+        (HExtlib.list_mapi
+         (fun (_,iname,_,cl) i ->
+           HExtlib.list_mapi
+            (fun (_,cname,_) j->
+              cname,NReference.reference_of_spec u (NReference.Con (i,j,leftno))
+            ) cl @
+           [iname,
+             NReference.reference_of_spec u
+              (NReference.Ind (inductive,i,leftno))]
+         ) il)
+  in
+   aliases := references @ !aliases
+;;
 
 let cache = NUri.UriHash.create 313;;
 
 
 (*                                                                        *)
 (**************************************************************************)
 
+(* ATTENZIONE: si puo' eseguire solo con MatitaC e dopo aver scelto
+   Debug → always show all disambiguation errors (that, moreover, slows
+   down the library a lot) *)
+
 include "nat/plus.ma".
 
 ndefinition thesis0: ∀A:Type.Type ≝ λA. A → A.
 
-alias id "thesis0" = "cic:/matita/tests/ng_commands/thesis0.def(0)".
-
 ndefinition thesis: ∀A:Type.Type ≝ λA. ?.
  napply (A → A);
 nqed.
 
-alias id "thesis" = "cic:/matita/tests/ng_commands/thesis.def(0)".
-
 ntheorem foo: ∀A:Type.thesis A.#A;#x;napply x;
 nqed.
 
-alias id "foo" = "cic:/matita/tests/ng_commands/foo.def(0)".
-
 ntheorem goo: ∀A:Type.A → A. #A; napply (foo ?);
 nqed.
 
-naxiom P: Prop.
-
-alias id "P" = "cic:/matita/tests/ng_commands/P.decl".
+naxiom NP: Prop.
 
-ndefinition Q: Prop ≝ P.
+ndefinition Q: Prop ≝ NP.
 
 nlet rec nzero (n:nat) : nat ≝
  match n with
   [ O ⇒ O
   | S m ⇒ nzero m].
 
-alias id "nzero" = "cic:/matita/tests/ng_commands/nzero.fix(0,0,0)".
-
 ntheorem nzero_ok: nzero (S (S O)) = O.
  napply (refl_eq ? O);
 nqed.