diff --git a/Makefile.in b/Makefile.in
index d28225033bc22035d21534c9b993c2cb4c177e21..fd6d066545eace9da0b84f5883399a8f18c036cd 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -50,6 +50,8 @@ OCAMLLIB = @OCAMLLIB@
 OCAMLBEST= @OCAMLBEST@
 OCAMLVERSION = @OCAMLVERSION@
 CAMLP4   = @CAMLP4O@
+PSVIEWER = @PSVIEWER@
+PDFVIEWER = @PDFVIEWER@
 
 INCLUDES = -I src/core -I src/util -I src/parser -I src/output \
            -I src/transform -I src 
@@ -409,8 +411,8 @@ wc:
 
 dep: 
 	$(MAKE) depend
-	cat .depend | ocamldot | dot -Tps > dep.ps
-	gv dep.ps
+	cat .depend | ocamldot | dot -Tpdf > dep.pdf
+	$(PDFVIEWER) dep.pdf
 
 # distrib
 #########
diff --git a/configure.in b/configure.in
index 5d7dae84510fab8a1fde0d09e600de8b2a77cf9e..16476c2b29816aa015d8328d37a54b328d57c6f7 100644
--- a/configure.in
+++ b/configure.in
@@ -422,6 +422,10 @@ else
     fi
 fi
 
+#Viewer for ps and pdf
+AC_CHECK_PROGS(PSVIEWER,gv evince)
+AC_CHECK_PROGS(PDFVIEWER,xpdf acroread evince)
+
 # substitutions to perform
 AC_SUBST(VERBOSEMAKE)
 AC_SUBST(EXE)
@@ -473,6 +477,8 @@ AC_SUBST(MIZARLIB)
 
 AC_SUBST(FORPACK)
 
+AC_SUBST(PSVIEWER)
+AC_SUBST(PDFVIEWER)
 # Finally create the Makefile from Makefile.in
 dnl AC_OUTPUT(Makefile)
 AC_OUTPUT(Makefile bench/bench)
diff --git a/src/core/context_utils.ml b/src/core/context_utils.ml
index a09ca1040eef805c1107502e48c27f001c89140b..80b5af9dbeec4c52d545b7731ab4ec8d3b3e321d 100644
--- a/src/core/context_utils.ml
+++ b/src/core/context_utils.ml
@@ -6,11 +6,5 @@ let cloned_from ctxt i1 i2 =
 (*  Format.printf "@[<hov 2>cloned (%a = %a)?: %a@]@\n" 
     print_ident i2 print_ident i1 
     print_ctxt ctxt;*)
-  let rec aux i =
-    i == i1 ||   
-      try 
-        let i3 = Mid.find i ctxt.ctxt_cloned in
-        List.exists aux i3
-      with Not_found -> false
-  in
-  aux i2
+  try i1 == i2 || Sid.mem i2 (Mid.find i1 ctxt.ctxt_cloned)
+  with Not_found -> false
diff --git a/src/core/theory.ml b/src/core/theory.ml
index 0ea70f99aad216b6c5e5dfea4c5a083df1579a40..a58e6c794e5794ec974a95d0e0b6cda4a95f9a3a 100644
--- a/src/core/theory.ml
+++ b/src/core/theory.ml
@@ -145,7 +145,7 @@ and namespace = {
 and context = {
   ctxt_decls : (decl * context) option;
   ctxt_known : decl Mid.t;
-  ctxt_cloned : ident list Mid.t;
+  ctxt_cloned : Sid.t Mid.t;
   ctxt_tag   : int;
 }
 
@@ -340,19 +340,23 @@ let empty_inst = {
 module Context = struct
 
   let empty_context = Hctxt.hashcons {
-    ctxt_decls = None;
-    ctxt_known = builtin_known;
+    ctxt_decls  = None;
+    ctxt_known  = builtin_known;
     ctxt_cloned = Mid.empty;
-    ctxt_tag   = -1;
+    ctxt_tag    = -1;
   }
 
   let push_decl ctxt kn d =
+    (* get the set of prototype symbols represented by [id] *)
+    let get_cl m id = try Mid.find id m with Not_found -> Sid.empty in
+    (* add a new association: [id'] represents [id] *)
+    let add_cl m (id,id') =
+      (* from now on [id'] represents [id] and everything
+       * that [id] represented at the moment of cloning *)
+      Mid.add id' (Sid.add id (Sid.union (get_cl m id) (get_cl m id'))) m
+    in
     let cloned = match d.d_node with
-      | Dclone l -> List.fold_left 
-          (fun m (i1,i2) ->
-             let l = try Mid.find i1 m with Not_found -> [] in
-             Mid.add i1 (i2::l) m)
-          ctxt.ctxt_cloned l
+      | Dclone l -> List.fold_left add_cl ctxt.ctxt_cloned l
       | _ -> ctxt.ctxt_cloned in
     Hctxt.hashcons 
       { ctxt with
@@ -878,7 +882,7 @@ let print_uc fmt uc = print_namespace fmt (Theory.get_namespace uc)
 let print_ctxt fmt ctxt =
   fprintf fmt "@[<hov 2>ctxt : cloned : %a@]"
     (Pp.print_iter2 Mid.iter Pp.semi (Pp.constant_string "->") 
-    print_ident (Pp.print_list Pp.simple_comma print_ident)) 
+    print_ident (Pp.print_iter1 Sid.iter Pp.simple_comma print_ident)) 
     ctxt.ctxt_cloned
 
 let print_th fmt th = fprintf fmt "<theory (TODO>"
diff --git a/src/core/theory.mli b/src/core/theory.mli
index d64bed6a20446b4c42af75c17c737bfdd0aab7e9..64781e708ef04734bc2c3c2fd5ff041fe2656c16 100644
--- a/src/core/theory.mli
+++ b/src/core/theory.mli
@@ -97,7 +97,7 @@ and namespace = private {
 and context = private {
   ctxt_decls : (decl * context) option;
   ctxt_known : decl Mid.t;
-  ctxt_cloned : ident list Mid.t;
+  ctxt_cloned : Sid.t Mid.t;
   ctxt_tag   : int;
 }
 
diff --git a/src/transform/inlining.ml b/src/transform/inlining.ml
index 67ea2bdf8a34b46a3b4008b9ad268f23b9403cda..efd5273531fab6acd2c85ba42a69d81d441adba1 100644
--- a/src/transform/inlining.ml
+++ b/src/transform/inlining.ml
@@ -12,14 +12,14 @@ type env = { fs : (vsymbol list * term) Mls.t;
 let empty_env = { fs = Mls.empty;
                   ps = Mls.empty}
 open Format
-
+(*
 let print_env fmt env =
   let print_map iter pterm pfs = Pp.print_iter2 iter Pp.newline Pp.comma pfs
     (Pp.print_pair (Pp.print_list Pp.comma Pretty.print_vsymbol) pterm) in
   fprintf fmt "fs:@[<hov>%a@]@\nps:@[<hov>%a@]@\n"
     (print_map Mls.iter Pretty.print_term Pretty.print_lsymbol) env.fs
     (print_map Mls.iter Pretty.print_fmla Pretty.print_lsymbol) env.ps
-
+*)
 let rec replacet env t = 
   let t = substt env t in
   match t.t_node with