Deontic logic is the logic that deals with actual as well as ideal behavior of systems. In this paper, we survey a number of applications of deontic logic in computer science that have arisen in the eighties, and give a systematic framework in which these applications can be classified. Many applications move in the direction of programming a computer in deontic logic to make the computer prohibit, permit or obligate people to do something. We discuss conditions under which this possibility is realistic and conditions under which it would be admissible to do so.

: The paper outlines ongoing research on logic-based tools for the analysis and representation of legal contracts, of the kind frequently encountered in large-scale engineering projects and complex, long-term trading agreements. We consider both contract formation and contract performance, in each case identifying the representational issues and the prospects for providing automated support tools. Keywords: Artificial Intelligence and Law; Contract Drafting; Document Assembly; Knowledge Representation. 1. Introduction Over the last twenty years or so a growing body of research in Artificial Intelligence has focussed on the representation of legislation and regulations (for a comprehensive discussion see (Sergot, 1991)). The motivation for this has been twofold: on the one hand there have been opportunities for developing advisory systems for legal practitioners; on the other hand the Law is a complex domain in which diverse modes of reasoning are employed, offering ample opportunity...

Most work in artificial intelligence and law has concentrated on modelling the type of reasoning done by trial lawyers. In fact, most lawyers' work involves planning -- for example, wills and trusts, real estate deals, and business mergers and acquisitions. Certain planning issues, such as the use of underspecified, or "open-textured" rules, are illustrated especially clearly in this domain. In this thesis, I set forth the characteristic features of planning in law, place it in the context of past artificial intelligence work in both law and planning, and describe CHIRON, a system that I have developed implementing my theory of open-textured planning in the domain of personal income tax law.

We propose an architecture for building expert systems in which the main subsystems are distinct but communicating programs: a Prolog inference engine, a multimedia interface tool and a data base management system. We have used this architecture for constructing a legal expert system for labour law. We propose a novel approach for capturing vague concepts. The vagueness is not represented in the sense that its extent is quantified but instead rules are given for evaluating the concept in a given situation. The method is analogous to legal practice; lawyers develop methods for judging whether vague concepts apply to fact situations. These methods are used for identifying the relevant subquestions and legal text documents for analyzing the case in issue. Our system reflects this and other aspects of a lawyer's practical work. This paper was presented at DEXA '90, the International Conference on Data Base and Expert Systems Applications, on 29--31 August 1990 in Vienna, Austria. This rese...

Increasing numbers of litigants represent themselves in court. Advisory systems designed to help litigants understand the available legal remedies and satisfy the substantive and procedural requirements to obtain those remedies have the potential to assist these litigants and thereby reduce the burden that they impose on the courts. This paper presents a four-component model of advisory systems for pro se litigants. This model was implemented in the Protection Order Advisory (POA), an advisory system for pro se Protection Order applicants. POA illustrates how existing inference, document-drafting, and interface-design techniques can be used to construct advisory systems for pro se litigants in a wide range of legal domains for which (1) determining whether a prima facie case is satis ed does not require opentextured reasoning, and (2) the documents required to initiate an action are characterized by homogeneity and simple structure.

tax case, was the principal illustration of a theory of legal reasoning and legal argumentation proposed more than ten years ago. Although the theory was described in some detail, using the vocabulary of prototypes and deformations, it was never fully implemented. There were two main problems: (1) the knowledge representation languages available at the time were not sufficiently expressive, and (2) as a result, the central concept of a prototype was never sufficiently formalized. These problems have been remedied by subsequent work, and the present paper describes an implementation (in PROLOG) of the original theory. A study of the implemented system provides a rational reconstruction of the arguments of Justice Pitney and Justice Brandeis in this seminal corporate tax case. 1

Pro se litigants constitute a growing burden to the judiciary. Advisory systems designed to help litigants understand the available legal remedies and satisfy the substantive and procedural requirements to obtain those remedies have the potential to reduce this burden. This paper presents a four-component model of advisory systems for pro se litigants. This model was implemented in the Protection Order Advisory (POA), an advisory system for pro se Protection Order applicants. POA illustrates how existing inference, document-drafting, and interface-design techniques can be used to construct advisory systems for pro se litigants in a wide range of legal domains for which (1) determining whether a prima facie case is satised does not require open-textured reasoning, and (2) the documents required to initiate an action are characterized by homogeneity and simple structure. 2 An Advisory System for Pro Se Protection Order Applicants 1 Introduction Increasing numbers of lit...

This paper discusses the potential for providing knowledge based support for the task of formulating policy, and determining what legislation is required to implement the policy. From a discussion of previous work in this area, certain major obstacles are identified. Chief among these is the need to match what the KBS can do with the way in which policy makers conceptualise and perform their task. Effective support can only be provided by a system which can be fully integrated into the working practice of its users. Some examples of an alternative approach, based on hypertext, are discussed, and some proposals for overcoming the obstacles with a combination of the hypertext and knowledge based approaches are given. 1.

Most case-based reasoning systems have used a single "best " or "most similar " case as the basis for a solution. For many problems, however, there is no single exact solution. Rather, there is a range of acceptable answers. We use cases not only as a basis for a solution, but also to indicate the boundaries within which a solution can be found. We solve problems by choosing some point within those boundaries. In this paper, I discuss this use of cases with illustrations from CHIRON, a system T have implemented in the domain of personal income tax planning. 1