pre.removeSucceedingOperator(replaceLit);
pre.addSucceedingOperator(new OperatorIDTuple(projection, index));
}
// Make ReplaceLit the successor of Projection
projection.removePrecedingOperator(replaceLit);
projection.setSucceedingOperator(new OperatorIDTuple(replaceLit, 0));
replaceLit.setPrecedingOperator(projection);
final HashSet<Variable> hsv = new HashSet<Variable>();