A theory of permission based on the notion of derogation

This paper presents a unifying theory of permission that integrates the concept of negative permission with three concepts of positive permission, namely explicit permission, exemption and antithetic permission. The concepts are defined and logically related by paying particular attention to the system of which they form part. A simple procedure for calculating the permitted actions that can be said to be implicit in a code of norms or a policy specification is then given.