// Delete empty ReplaceVar
if (replaceVar.getSubstitutionsVariableLeft().size() == 0) {
final OperatorIDTuple succ = replaceVar.getSucceedingOperators()
.get(0);
pat.addSucceedingOperator(succ);
pat.removeSucceedingOperator(replaceVar);
succ.getOperator().removePrecedingOperator(replaceVar);
succ.getOperator().addPrecedingOperator(pat);
rootOperator.deleteParents();
rootOperator.setParents();