The British Nationality Act as a logic program (1986) [pdf]

Very interesting. The demo on pp 376 looks useful.

From the conclusion:

> The British Nationality Act 1981 has also proved to be a rich source of problems for the use of logic for knowledge representation. It has highlighted problems with negation as failure and counterfactual conditions in particular. We believe that the formalization of legislation and the development of computer systems to assist with legal problem solving and decision making provide a rich domain for developing and testing artificial intelligence technology. More tentatively, the accumulated experience of managing complex systems of law may teach us something about the maintenance of large bodies of complex software.

Here's another paper by one of the authors, "Legislation as Logic Programs" from 1991: http://www.doc.ic.ac.uk/~rak/papers/law.html

> In addition to the resemblance between legislation and programs, the law has other important similarities with computing. It needs for example to validate legislation against social and political specifications, and it needs to organise, develop, maintain and reuse large and complex bodies of legal codes and procedures. Such parallels between computing and law suggest that it might be possible to transfer useful results and techniques in both directions between these different fields. One possibility explored in this paper is that the linguistic structures of an appropriately extended logic programming language might indicate ways in which the language of legislation itself could be made simpler and clearer.