An ontology of changes in normative systems from an agentive viewpoint

Defeasible deontic logic has shown to be expressive enough to represent a normative system, and therefore compliance to such a system can be automatically checked by means of classical model checking techniques of logical systems. However, normative systems are not static, as they can be actively changed by the legislator over time, directly, by changing one norm. Moreover norms can change passively, either by effect of the change of another piece of the normative system, or by means of the change of meaning that affects terms employed in the norm. Although some efforts have been carried out by scholars in the field of legal reasoning about norm change, there is a lack of uniformity in the representation of these changes, and this is an issue when we aim at deploying the law as an automated platform: we need to introduce changes as effects in the semantics of derivation in a logical system, when the unified viewpoint admits a unified representation as well. We adopt the logical paradigm of agency and provide a classification of changes from an agentive viewpoint that allows a unified representation within the logical language for agents LegalRuleML.