Reasoning about norms and time is of central concern to the regulation or control of the behavior of a multi-agent system. In earlier work we introduce a representation of normative systems that distinguishes between norms and the detached obligations of agents over time. In this paper we consider constitutive norms and the detached counts-as conditionals and institutional facts in this framework, we introduce deadlines in the regulative norms, and we consider the corresponding role of violations. We focus on the reasoning tasks to determine whether a constitutive or regulative norm is redundant in a normative system and whether two normative systems are equivalent. We distinguish counts-as equivalence, institutional equivalence, obligation equivalence and violation equivalence, depending on whether we are interested in all normative consequences, or only a subset of them. For the various notions of equivalence, we give sound and complete characterizations.
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