public static Stella_Object negateConstraint(IntegerWrapper missingArgument, NumberWrapper x1, NumberWrapper x2) {
    { Stella_Object value = null;

      switch (missingArgument.wrapperValue) {
        case -1: 
          value = (PlKernelKb.arithmeticEqualTest(x1, PlKernelKb.negateComputation(x2)) ? Stella.TRUE_WRAPPER : Stella.FALSE_WRAPPER);
        break;
        case 0: 
          value = PlKernelKb.negateComputation(x2);
        break;
        case 1: 
          value = PlKernelKb.negateComputation(x1);
        break;
        default:
        break;
      }
      return (value);
    }
  }