In this paper, an abstract model of the law is presented that has three pri
mitives: states of affairs, events and rules. The starting point of the abs
tract model is that the law is a dynamic system of states of affairs which
are connected by means of rules and events. The abstract model can be regar
ded as a top ontology of the law, that can be applied to legal knowledge re
presentation. After an elaboration of the three primitives, the uses of the
abstract model are illustrated by the analysis of central topics of law. T
hen we discuss heuristic guidelines for legal knowledge representation that
are suggested by the abstract model. The paper concludes with a comparison
with related work. The appendix contains a formalism for the abstract mode
l. (C) 1999 Academic Press.