(C+)++: An action language for modelling norms and institutions

Abstract

The language C+ of Giunchiglia, Lee, Lifschitz, McCain, and Turner (2004) is a formalism for specifying and reasoning about the e ects of actions and the persistence (`inertia') of facts over time. An `action description' in C+ is a set of C+ laws which de ne a labelled transition system of a certain kind. This document presents (C+)++, an extended form of C+ designed for representing norms of behaviour and institutional aspects of (human or computer) societies. There are two main extensions. The rst is a means of expressing `counts as' relations between actions, also referred to as `conventional generation' of actions. The second is a way of specifying the permitted (acceptable, legal) states of a transition system and its permitted (acceptable, legal) transitions.