anchor.diff:                      link(Pid),
                       Pid ! ?VECTOR_MSG(Lid, VC),
                       receive
  -                        ?VECTOR_MSG(PidsLid, ok) -> ok;
  +                        ?VECTOR_MSG(_PidsLid, ok) -> ok;
                           {'EXIT', Pid, _Reason} ->
                               %% Process may have been asked to exit.
                               ok                                                        
  
positive.code:     NewNexts = dict:store(Lid, Next, Nexts),
      {NewEnabled, NewBlocked} =
          update_lid_enabled(Lid, Next, Enabled, Blocked),
      WakedSleepSet = remove_awaked(SleepSet, Nexts, Selected),
      NewSleepSet =
          case dict:find(Lid, SleepMap) of
              error -> WakedSleepSet;
              {ok, NewSleeping} ->
                  ?f_debug("Sleeping: ~w\n",[NewSleeping]),
                  ordsets:union(NewSleeping, WakedSleepSet)
          end,        
      CommonNewTraceTop =
          #trace_state{i = NewN, last = Selected, nexts = NewNexts,
                       enabled = NewEnabled, blocked = NewBlocked,
  
negative.code:             add_all_backtracks_trace(Transition, ClockVector, Trace, [StateI|Acc]);
          true ->
              ?f_debug("~p: I:~p ~p\n",[Transition, I, SI]),
              [#trace_state{enabled = Enabled, backtrack = Backtrack, sleep_set = SleepSet} =
                   PreSI|Rest] = Trace,
              P = pick_from_E(ordsets:subtract(Enabled, SleepSet), I, ClockVector),
              NewBacktrack = ordsets:add_element(P, Backtrack),
              NewSleepSet = ordsets:add_element(ProcSI, SleepSet),
              ?f_debug("      New backtrack: ~w\n", [NewBacktrack]),
              NewPreSI =
                  PreSI#trace_state{backtrack = NewBacktrack, sleep_set = NewSleepSet},
              lists:reverse(Acc, [StateI,NewPreSI|Rest])
      end.
  
  