Relevance, Derogation and Permission

Abstract. We show that a recently developed theory of positive permission based on the notion of derogation is hampered by a triviality result that indicates a problem with the underlying full-meet contraction operation. We suggest a solution that presupposes a particular normal form for codes of norms, adapted from the theory of relevance through propositional letter sharing. We then establish a correspondence between contractions on sets of norms in input/output logic (derogations), and AGM-style contractions on sets of formulae, and use it as a bridge to migrate results on propositional relevance from the latter to the former idiom. Changing the concept accordingly we show that positive permission now incorporates a relevance requirement that wards off triviality. Key words: Positive permission, antithetic permission, derogation, relevance, norm-system dynamics.

• Type: Conference
• Year: 2010
• Where: DEON
• Authors: Audun Stolpe
• Keywords: Automated Reasoning, DEON 2010, Full-meet Contraction Operation, Positive Permission, Propositional Letter Sharing