ProjectionElemList projElemList = new ProjectionElemList();
projElemList.addElement(new ProjectionElem(subjVar.getName(), "subject"));
projElemList.addElement(new ProjectionElem(predVar.getName(), "predicate"));
projElemList.addElement(new ProjectionElem(objVar.getName(), "object"));
result = new Projection(result, projElemList);
return result;
}