private String convertNextStateTransitions(ContextState state, KripkeStructureModel kripkeModel) {
    StringBuffer buffer = new StringBuffer();
    Iterator<String> symbolsIt = null;
    ContextPropositionAssignment assignment = state.getAssignment();
    if (assignment.size() > 0) {
      symbolsIt = assignment.getSymbols().iterator();

      while (symbolsIt.hasNext()) {
        String symbol = symbolsIt.next();
        if (assignment.getValuationOf(symbol)) {
          buffer.append(symbol);
        } else {
          buffer.append("!" + symbol);
        }
        if (symbolsIt.hasNext()) {
          buffer.append(" & ");
        }
      }
      String currentState = buffer.toString();
      buffer = new StringBuffer();
      int[] nextStatesId = state.getNextStatesId();
      Set<ContextState> nextStates = new LinkedHashSet<ContextState>();
      for (int nextStateId : nextStatesId) {
        nextStates.add(kripkeModel.getState(nextStateId));
      }

      Iterator<ContextState> nextStatesIt = nextStates.iterator();

      while (nextStatesIt.hasNext()) {
        ContextState next = nextStatesIt.next();
        buffer.append("(" + currentState + " & ");
        ContextPropositionAssignment nextAssignment = next.getAssignment();
        symbolsIt = nextAssignment.getSymbols().iterator();
        while (symbolsIt.hasNext()) {
          String symbol = symbolsIt.next();
          if (nextAssignment.getValuationOf(symbol)) {
            buffer.append(symbol + "'");
          } else {
            buffer.append("!" + symbol + "'");
          }
          if (symbolsIt.hasNext()) {
            buffer.append(" & ");
          }
        }
        buffer.append(")");
        if (nextStatesIt.hasNext()) {
          buffer.append(" |\n");
        }
      }
    }
    return buffer.toString();
  }
 private String convertInitialState(ContextState state) {
   ContextPropositionAssignment assignment = state.getAssignment();
   Iterator<String> symbols = assignment.getSymbols().iterator();
   StringBuffer buffer = new StringBuffer();
   while (symbols.hasNext()) {
     buffer.append("!" + symbols.next());
     if (symbols.hasNext()) {
       buffer.append(" & ");
     }
   }
   return buffer.toString();
 }