3.3 Metapolicies at the Imperial College

In [LuSl 97d], [LuSl 97a], and [LuSl 97b] metapolicies are used as a way to specify logical predicates over different policies, which were described in section .

They are introduced because conflicts may arise between policies applied to the same object processing different management functionalities, or policies are applied to objects which are members of several domains.

The metapolicies are policies about permitted policies and their only purpose is to specify application specific consistency constraints pertaining the contents of policies in one domain. They can be expressed as logical predicates applying to sets of policy objects within a domain. Table  shows the predicate specifying a conflict as an example where a conflict of duties exists: The same manager cannot both authorise payment and sign the payment cheque.

Table 3.5: Predicate of a metapolicy [LuSl 97b]

At the Imperial College the predicates are translated into Prolog statements in order to find conflicts in a developed policy-based system.