+if (List.map fst exp_named_subst'' <> List.map fst (List.filter (fun (uri,_) -> List.mem uri params) exp_named_subst) @ List.map fst exp_named_subst') then (
+debug_print (lazy "\n\n---- BEGIN ") ;
+debug_print (lazy ("----params: " ^ String.concat " ; " (List.map UriManager.string_of_uri params))) ;
+debug_print (lazy ("----S(" ^ UriManager.string_of_uri uri ^ "): " ^ String.concat " ; " (List.map (function (uri,_) -> UriManager.string_of_uri uri) exp_named_subst))) ;
+debug_print (lazy ("----P: " ^ String.concat " ; " (List.map (function (uri,_) -> UriManager.string_of_uri uri) exp_named_subst'))) ;
+debug_print (lazy ("----D: " ^ String.concat " ; " (List.map (function (uri,_) -> UriManager.string_of_uri uri) exp_named_subst''))) ;
+debug_print (lazy "---- END\n\n ") ;
+);