Exercising access rights can result in creating new objects and defining new policies. In the conceptual schema this is represented as adding an element to the corresponding set. As we discussed in the previous section, changes in membership of the sets 6#6 and 7#7 depend entirely on the set 5#5.
The deletion of an element from the sets 5#5, 6#6 or 7#7 entails deletion of each element from 9#9 in which the deleted element appears. To simplify our model we require that rights can be applied only to the elements of set 5#5. If we allow rights to be applied to the elements of 9#9, we will have to consider a policy management model.