Law in the Information Society: 5th International Conference of the Institute of Legal Documentation (IDG) of the Italian National Research Council, December 2-5, 1998, Florence. Legal Contract Drafting at the Micro-Level Aspassia Daskalopulu Dept of Information Systems and Computing Brunel University, Uxbridge Middlesex UB8 3PH, UK. E-mail: Aspassia.Daskalopulu@brunel.ac.uk Abstract This paper reports on research whose general aim has been to explore the potential for developing logic-based tools for the analysis and representation of legal contracts [Daskalopulu 1998]. The intended applications of such representation include both the drafting of new contracts and the management and administration of existing ones, that is to say, the general problem of storing and retrieving information from large contractual documents, and more specific tasks such as monitoring compliance or establishing parties’ duties/rights under a given agreement when it is in force. Experimental material is drawn mostly from engineering contracts, which are typically large and complex and contain a multitude of interrelated provisions. The term ‘contract’ is commonly used to refer both to a legally binding agreement between (usually) two parties and to the document, that records such an agreement. A previous paper [Daskalopulu & Sergot 1995] was concerned with documents and the representation of contracts at the macro-level : the emphasis is on issues relevant to the design of structurally coherent documents. This paper deals with the contents of agreements and representations at the micro-level. Micro-level drafting is the source of a host of issues ranging from representing the detailed wording of individual sections, to representing the nature of provisions (obligations, powers, reparations, procedures), to representing their "fitness" or effectiveness in securing some party's best interests. The implications of these issues for knowledge elicitation and representation were discussed in [Daskalopulu & Sergot 1997]. Various techniques are available to assist in aspects of this task, such as disambiguating contractual provisions and in detecting inconsistency or incompleteness (for example [Allen & Saxon 1993], [Alchourrón & Bulygin 1971], [Jones & Sergot 1993; 1996]). The paper discusses a number of such techniques and seeks to identify the limits on their applicability in the domain of legal contracts. 1 Introduction This paper reports on aspects of a broader research project that seeks to develop logic-based tools for the drafting of legal contracts, their management and administration. ‘ Drafting’ refers to the problem of creating new contracts, ‘ management’ refers to the general problem of storing and retrieving related documents or parts of them and ‘ administration ’ refers to more specialised tasks, such as monitoring the compliance of contracting parties with a given agreement, or advising them on the effects of individual provisions and their applicability. In the context of this research emphasis has been placed on the drafting process: developing representations of contracts for this task provides a main generic framework on which specialised tools for management and administration can be attached as extensions that manipulate such representations. The importance of drafting is particularly evident in the case of engineering contracts and long-term trading agreements. This is because such contracts are typically large, often running to hundreds of pages and accompanied by technical drawings and special schedules. As such agreements are long-term, a large number of issues need to be addressed in the corresponding documents. Consequently, the documents contain a multitude of interrelated provisions. The drafting of a new contract is a lengthy process where several drafts are created and negotiated upon. As English Contract Law holds that written agreements contain all and only that which the parties 2 have agreed upon (the parole evidence rule, cf. [Atiyah 1989]), it is important not to make mistakes or omissions as these might yield significant financial consequences should litigation arise. The term ‘ contract’ is commonly used to refer both to a legally binding agreement between (usually) two parties and to the document that is used to record such agreement when the latter is put in writing. This research draws on this distinction and separates the problem of designing documents from the problem of designing agreements. Earlier work on the drafting of legislation [Bench-Capon 1987] drew a distinction between the formulation of policies and their implementation via legislative text. An analogy can be made whereby the formulation of a policy is similar to the formulation of a specification (in software engineering terms) and is carried out by Parliament or the appropriate policy-making body. The drafting of legislation, extending this analogy, is then akin to programming; the drafted legislation is intended to implement the specification —the policy that was formulated. A similar analogy can be made for the case of contracts. The agreement between two parties is negotiated and finalised as a specification of the goals that the business exchange it regulates is meant to achieve. The document that records it is the implementation of such specification. When developing tools for contract drafting, however, it is difficult to demarcate precisely what is relevant to the design of documents from what is relevant to the design of agreements. Usually the people involved in the negotiation of agreements are also often responsible for the production of the documents. Moreover these two stages in contract formation are often interrelated: what is agreed between the parties is what must be implemented in the document, yet it is often the document itself that is being negotiated, for example what aspects of the business exchange it will refer to, in what level of detail and often in what form of particular wording. By drawing explicitly on the distinction between documents and agreements, however, some aspects of this process are facilitated, especially in cases where the creation of new contracts is based on previous examples or model forms. Hence, contract drafting can be discussed at two levels: (i) At the macro-level, the emphasis is in producing structurally coherent documents that implement an agreed specification. (ii) At the micro-level, the emphasis is in producing well-formed documents that implement an agreed specification and indicate whether the agreed specification is well formed. A previous paper [Daskalopulu & Sergot 1995] discussed contract drafting at the macro-level. There the process of constructing a new document, in the presence of existing previous examples or model forms, is regarded as similar to computer-aided design subject to constraints. Drafters use pre-prepared blocks of text in order to construct a new document of a particular kind, much in the same way that a graphics designer uses geometric shapes to construct a picture. This approach adopted the idea that a document can be assembled from its components (cf. [Fiedler 1985], [Gordon 1992]) but extended it further: the assembly process is subject to a collection of explicitly stated constraints that govern the structure of documents. These constraints express relationships between document components and their satisfaction ensures that the output of the assembly process is a structurally coherent document. A computational model of this approach was produced where the structure and interrelationships between constituent parts of documents were represented rather than the text of the 3 document itself. That is, the representation of contractual documents at the macro-level does not capture information about what a contract actually says or prescribes (what it ‘ means’ ). This paper is concerned with contract drafting at the micro-level, where the issue of interest is the formulation of individual provisions ensuring that the overall document is well formed. Section 2 considers criteria for well-formed individual provisions and documents. Section 3 discusses a number of techniques that are available to address some of these criteria. It should be noted at this point that in the course of this research an important observation came to light. Contrary to expectations, the sample contractual documents that were examined do not contain all of the content of the corresponding agreement. This is because where a legislative Act exists, which regulates trading agreements of some type, the provisions of the Act are implied into agreements of that type (for example sales contracts conform with the Sale of Goods Act). To attempt therefore complete representation of contractual content we would need to represent domain information and relevant legislation. In this research, the focus has been on the representation of agreements as these emerge from an examination of their associated documents. The resulting representation is therefore not complete in the sense mentioned earlier. 2 Well-formed contractual provisions At the micro-level, the drafter’ s quest is for well-formed documents. A question that arises naturally is what makes a contractual document well formed. The obvious but rather vague answer is that the document should accurately implement the agreement on which the parties negotiated. A whole host of issues emerge from this, such as what makes a particular provision ‘ good ’ for a party in terms of the party ’ s expectations from the agreement and its broader goals, what implications does a provision entail and so on. In [Daskalopulu & Sergot 1997] some of these issues were discussed in more detail with suggestions of the areas of research that might prove useful in addressing them. This paper concentrates on issues of consistency and completeness, but touches upon the roles that provisions serve. The sample contracts that were examined during the course of this research highlighted the following roles that provisions play: (i) Descriptive: Such provisions provide definitions and guidance as to how certain terms are to be interpreted and used in the context of the contract. The term “Day” for example may be defined to mean some period not necessarily comprising 24 hours. (ii) Prescriptive : Such provisions determine certain behaviour for the parties by specifying actions that must/may/must not be taken or states of affairs that must/may/must not obtain. Usually such prescriptions are accompanied by a specification of circumstances or time periods where the required behaviour is to take place. (iii) Procedural: Such provisions specify procedures that need to be followed by parties in order for certain states of affairs to be established. Aspects of an agreement that are usually 4 accompanied by such procedural specification include the appointment of experts or arbitrators to settle disputes, the processing of financial claims, the change of delivery times or quantities, the early termination of the agreement and so on. (iv) Algebraic : Such provisions specify formulae that are to be used to calculate values for various parameters of the agreement, such as the price of goods during particular periods or adjustments to prices or quantities of goods. (v) Effective: Such provisions specify conditions under which other provisions apply. These are sometimes referred to as secondary provisions. The list is not intended to be an exhaustive or formal classification of contractual provisions. A particular contract clause may be of more than one of the aforementioned kinds. For example an individual provision may prescribe an obligation and at the same time define a term (and likewise for the other kinds of functions). Rather the purpose of the list is to indicate the kinds of clauses that drafters put together when creating new contractual documents and to motivate the ensuing discussion on what makes a provision ‘well-formed ’ . Some criteria for well-formed provisions seem therefore to be: (i) Performance: Is a given provision a good implementation of the corresponding part of the agreement? In other words, does it have the required effect or any undesirable side effects? This consideration gives rise to the issue of ambiguity : Where a given provision is formulated in such a way that multiple interpretations can be ascribed to it, which is the one intended by the parties? (ii) Consistency : Is a given set of provisions concerning an aspect of the agreement consistent? If more than one provision apply under some given circumstances, are they in conflict? (iii) Completeness: Is a given set of provisions concerning an aspect of the agreement complete? In other words, does it cater for all the intended circumstances that might arise? (iv) Redundancy : Can one or more provisions be simplified to remove unwanted redundancy? This is perhaps particularly the case for algebraic provisions where certain parameters in formulae could be unfolded to yield a simplified formula. Various techniques, practical and theoretical, have been developed that might be employed to address such issues. The following section reviews the most known ones and seeks to identify the extent to which they can be usefully applied to legal contracts. 3 Techniques Four approaches, which are to some extent interrelated in terms of their goals, are discussed. Logic programming representations offer executable specifications that are useful in addressing performance, consistency and completeness. Normalised Legal Drafting aims at removing unwanted ambiguity. Case Analysis provides a theoretical framework for analysing a set of norms with a view 5 to determine consistency, completeness and redundancy. Finally, the Normative Positions approach offers the means to address performance and consistency. Of the four approaches, Logic Programming is the one that does not purport to represent legal notions (such as duty, right, obligation and so on) by employing any form of deontic logic. 3.1 Contractual Provisions as Logic Programs A detailed representation of contractual provisions could follow in the same steps of a popular approach for the representation of legislation or regulations where provisions are represented as logic programs. The most celebrated instance of this approach is the formalisation of the British Nationality Act 1981 [Sergot et al. 1986]. Social security regulations [Hammond 1983] and Indian civil service pension rules [Sergot 1991] are also amongst the areas where the approach was tried successfully (for an overview of the approach cf. [Sergot 1988]). 3.1.1 Overview The following example reproduced from [Kowalski 1995] illustrates the approach on a subsection of the British Nationality Act 1981: 1(1) A person born in the United Kingdom after commencement shall be a British citizen if at the time of the birth his father or mother is— (a) a British citizen; or (b) settled in the United Kingdom. This can be paraphrased in logic programming form as follows, where predicates are in infix notation and variables in upper case: X acquires british citizenship by section 1.1 if X is born in the uk at time T and T is after commencement and Y is parent of X and Y is a british citizen at T or Y is settled in the uk at T The main feature of this approach is the close resemblance between the legislative or regulatory text and its corresponding formulation as a logic program. Hence, the representation of such text maintains a clarity that renders its inspection, verification, modification and extension easier to perform than on algorithmic representations. Legislation or large sets of regulations typically contain heavy amounts of cross-references, with special cases or exceptions to rules appearing at different parts of a document or even in different documents; to attempt an algorithmic representation is a cumbersome task. Moreover, legislative and regulatory text may be ambiguous as it is expressed in natural language. Such ambiguity may be syntactic or semantic. Sergot [1988] cites the example of regulations under which a woman could receive a ‘Housewives Non-Contributory Invalidity Pension’ (H NCIP), where one provision states that a woman would be entitled to H NCIP “if she is incapable of performing her normal household 6 duties to a substantial extent”. The scope of ‘ to a substantial extent ’ is not clearly defined. Moreover, the term itself is vague as what constitutes ‘ substantial extent ’ might be different things to different people. Open-textured concepts are abundant in legislative and regulatory text and an advantage of the logic programming approach is that multiple interpretations may be supported within the same representation as different logic programs. The main benefit of logic programming representations of legislative or regulatory text is that they constitute executable specifications. Hence, drafters or policy-makers can ascertain whether the provisions they are creating have the desired effect or any unwanted side effects by ‘ executing ’ the model. 3.1.2 Application Having reviewed briefly the main features of the approach, let us now see to what extent it can be usefully applied to the representation of contractual provisions. As Sergot points out [1988], provisions that are essentially descriptive in nature admit logic programming formulation in a straightforward manner. That is for provisions which specify conditions under which an entity X is to be classified as being of type Y we can construct corresponding logic programs with relative ease. Consider for example the following extract from a sample contract [IEE 1988]: (46) Force Majeure means:-—war, hostilities (whether war be declared or not), invasion, act of foreign enemies; —ionising radiations, or contamination by radio-activity from any nuclear fuel, or from nuclear waste from the combustion of nuclear fuel, radio-active toxic explosive, or other hazardous properties of any explosive nuclear assembly or nuclear component thereof; —pressure waves caused by aircraft of other aerial devices travelling at sonic or supersonic speeds; —rebellion, revolution, insurrection, military or usurped power or civil war; —riot, civil commotion or disorder; —any circumstances beyond the reasonable control of either of the parties. It is not difficult to construct a logic program for classifying an incident as Force Majeure. In fact, such a representation may take various syntactic forms, one of which is shown below: fm_circumstance(war). fm_circumstance(hostility). fm_circumstance(invasion). : force_majeure(Episode) fm_circumstance(Episode). force_majeure(Episode) beyond_parties_reasonable_control(Episode). Such a representation might be useful for drafters if they want to establish quickly what circumstances are covered under such a definition—though with the last sub-clause any circumstance 7 is pretty much covered if it is deemed to be beyond the reasonable control of the parties, and what is ‘ reasonable control ’ is open-textured. Logic programs can also be constructed for prescriptive provisions if we regard them as qualifications, that is statements specifying legal relations for the parties in given conditions. For example, the following is a provision from the section on ‘ Contractor’ s Obligations ’ of a sample contract [IEE 1988]: (14.4) The Contractor shall not without the Engineer’s consent make any material alteration to the approved Programme. This might be regarded as defining an obligation for the Contractor to refrain from performing a certain action in given conditions. A logic programming formulation of this clause might go along the lines: The contractor is obliged by section 14.4 to not alter the programme P if there does not exist consent by the engineer to alter the programme P. Consider also the following example from the same sample contract: (14.1) Within the time stated in the Contract or, if no time is stated within 30 days after the Letter of Acceptance, the Contractor shall submit to the Engineer for his approval the Programme for the execution of the Works showing: -(a) the sequence and timing of the activities by which the Contractor proposes to carry out the Works (including design, manufacture, delivery to site, erection and testing), (b) the anticipated numbers of skilled and unskilled labour and supervisory staff required for the various activities when the Contractor is working on Site, (c) the respective times for submission by the Contractor of drawings and operating and maintenance instructions for the approval thereof by the Engineer, (d) the times by which the Contractor requires the Purchaser (i) to furnish any drawings or information, (ii) to provide access to Site, (iii) to have completed any necessary civil engineering or building work (including foundations for the Plant), (iv) to have obtained any import licences, consents, wayleaves, and approvals necessary for the purposes of the Works, (v) to provide electricity, water, gas, and air on the Site or any equipment, materials or services which are to be provided by the Purchaser. This section specifies an obligation on the part of the Contractor to submit a Programme of a specified description to the Engineer within a specified time. A logic programming representation of such an obligation might go along the lines: The contractor is obliged by section (14.1) to submit an acceptable programme P at time T if T is the time specified in the contract. The contractor is obliged by section (14.1) to submit an acceptable programme P at time T if there exist a letter of acceptance at time T1 and T is later than T1 by 30 days. 8 The representation could be extended by an appropriate definition for what makes an acceptable programme according to section (14.1). This is certainly neither the only nor the best way to represent the prescriptions above. The purpose of the example is to illustrate a point made by Jones and Sergot [1992]: Prescriptive statements can be regarded as definitional and be represented as logic programs if one wants to retrieve such information or to construct a system that operates as they specify. Where it is important to maintain the distinction between what ought to be the case and what actually is the case, however, such representations fail, as they do not accommodate the possibility that norms might in practice be violated. The representation of section (14.1) above, for instance, is useful if all we want to establish is what obligation the contractor has with respect to this section, what action on his part is characterised by this obligation and when such obligation is to be carried out. There are no means of establishing what follows from such an obligation; for example what happens if the contractor violates it and, relevant to that, what constitutes violation—the non-performance of the act within the specified time period, the non-conformance of the programme to the standards set out in the contract or both? Jones and Sergot conclude that in cases where we want to reason with the distinction between the ideal and the actual some form of deontic logic is required. 3.2 Normalised Legal Drafting Since 1957, Allen has been advocating the use of symbolic logic as a tool for drafting legislative text. Allen’ s project is specifically targeted at ambiguity arises from natural language. Allen [1982] claims that a large amount of litigation based on written instruments can be traced to the drafter ’ s failure to convey his meaning clearly. Such ambiguity is not always of the same kind; sometimes it may be deliberate, because the drafter wishes the legal text to be open to various interpretations for political or social reasons; yet, frequently, such ambiguity is inadvertent and arises from the way natural language is used as a means to formalise and represent the drafter ’ s intentions. In addition, such ambiguity is not always the result of what is written, but of what is omitted as well. Allen classifies various kinds of imprecision and concentrates on syntactic ambiguity that arises from the relations between sentences. He proposes a normalised language in which the different nuances of the meaning of logical connectives and terms are reflected by the use of appropriately marked words. The following table shows the basis of his classification for the use of terms: DEFINED TERM 1. INTENDED IN THE DEFINED SENSE DEFINED TERM o 2. Intended in the ordinary language sense DEFINED TERM a 3. Intended to be ambiguous about whether occurrence is in defined sense or ordinary language sense defined term 4.(a) Drafter thought about problem, intended to be ambiguous about whether this occurrence is in defined sense or ordinary language sense, but does not wish to tell audience about this deliberate choice OR (b) Drafter did not think about the problem of whether this occurrence is in the defined sense or ordinary language sense. Table 1 Allen’s [1982] classification of defined terms 9 As regards connectives used to express relations between sentences Allen [1957] proposes formal definitions that can be used to disambiguate between, for instance, inclusive and exclusive disjunction, or between the use of “if …then ” statements and “if and only if” statements. In his framework, all natural language statements are normalised ( “systematically pulverized”). The process of normalisation assists both in the interpretation of legislative provisions and the drafting of new ones. In the case of the former, this is because implicit relations between propositions become explicit by ascribing precise meaning to connectives and terms. In the case of the latter, this is because the drafter becomes aware of the different possible interpretations that might be ascribed to his text and has the option to remove inadvertent ambiguity by trying to reformulate his text so that the only possible interpretation is the intended one. The following example illustrates the motivation and the result of their proposal. It concerns the University of Michigan lease termination: The University may terminate this lease when the Lessee, having made application and executed this lease in advance of enrolment, is not eligible to enrol or fails to enrol in the University or leaves the University at any time prior to the expiration of this lease, or for violation of any provisions of this lease, or for violation of any University regulation relative to Resident Halls or for health reasons, by providing the student with written notice of this termination 30 days prior to the effective time of termination, unless life, limb, or property would be jeopardized, the Lessee engages in the sales or purchase of controlled substances in violation of federal, state or local law, or the Lessee is no longer enrolled as a student or the Lessee engages in the use or possession of firearms, explosives, inflammable liquids, fireworks, or other dangerous weapons within the building or turns in a false alarm in which cases a maximum of 24 hours notice would be sufficient. [Emphasis added]. The clause consists of a single sentence with the ambiguous form: A if A1 and A2 or A3 or A4 or A5 or A6 or A7 unless B1 or B2 or B3 or B4 or B5 in which cases B. Depending on how this is bracketed different interpretations arise. Allen and Saxon identify approximately 80 clarification questions that may be required in order to disambiguate between all possible interpretations and as a result of such a process they conclude that the intended interpretation is: ((A if ((A1 and (A2 or A3)) or A4 or A5 or A6 or A7)) if not (B1 or B2 or B3 or B4 or B5)) and (if (B1 or B2 or B3 or B4 or B5) then B). and (if not (B1 or B2 or B3 or B4 or B5) then not B. Here ‘when’ is taken to mean ‘ if ’ , ‘unless’ is taken to mean ‘ if not’ and ‘ in which cases ’ is taken to mean ‘ if and only if ’ . Had both ‘when’ and ‘ in which cases’ be taken to mean ‘ if ’ the resulting interpretation would be: ((A if (A1 and (A2 or A3)) or A4 or A5 or A6 or A7)) if not (B1 or B2 or B3 or B4 or B5) and if (B1 or B2 or B3 or B4 or B5) then B). Kowalski [1995] argues that logic programming representations are superior because they render many of the possible interpretations that might arise logically implausible. Kowalski ’ s formulation of the University of Michigan lease termination clause is: A if A1 and A2 and not B. A if A1 and A3 and not. A if A4 and not B. A if A5 and not B. A if A6 and not B. A if A7 and not B. 10 B if B1. B if B2. B if B3. B if B4. B if B5. In this the condition not (B1 or B2 or B3 or B4 or B5) has been replaced by the simpler condition not B (under the assumption that B1– B5 are the only conditions under which B holds). Kowalski [1995] points out however, that in logic programming there is no difference between the representation of ‘ if ’ and the representation of ‘ if and only if ’ as the closed world assumption operates and the logical consequences of a program include those of its completion. Therefore, the two interpretations produced by Allen and Saxon correspond to the same logic program. If we were interested in establishing the effects of a given set of provisions, the logic programming formulation above would account for two of Allen ’ s interpretations. Moreover, the logic programming representation can easily be turned into a natural language expression that is much clearer than the original clause, and more concise than the natural language expression corresponding to Allen and Saxon ’ s representation. Given the fact that logic programs provide executable specifications, as was stated in the previous section, there does not seem to be any advantage to Normalised Legal Drafting over Logic Programming. More recently, [Allen & Saxon 1993] the framework was extended with explications of Hohfeld ’ s [1913] fundamental legal conceptions to cater for normative statements. These are the legal notions identified by Hohfeld as the “l(fā)owest common denominators” through which all other legal relations may be defined. Hohfeld organised them into pairs of jural opposites and jural correlatives and they are summarised in the following tables; relations appearing in the same column are opposites whereas relations along the same diagonal are correlatives. Terms such as ‘right ’ , ‘privilege ’ , ‘ power’ , ‘ entitlement ’ and so on are often conflated whereas they entail different things as pointed out by Hohfeld. Right Privilege Power Immunity No-right Duty Disability Liability Table 2 Hohfeld ’ s Fundamental Legal Conceptions Allen and Saxon’ s extended language for normalised legal drafting is the core of the MINT system in which a lawyer-user is asked to determine his intended interpretation of a given statement when presented by a set of alternatives produced by the system. It is not altogether clear whether the user ’ s choices at one point of the consultation session progressively narrow the space of available interpretations, that is, whether the user ’ s commitment to some interpretation for part of the legislative or regulatory text entails commitments to particular interpretations for other parts of the text, by restricting choices to those that would be consistent with previous ones. This is the kind of functionality offered by Sergot ’ s [1998] automated analysis of normative positions. 11 3.3 Case Analysis Carlos Alchourrón and Eugenio Bulygin [1971] provide an explication for consistency, completeness and independence, the formal properties of normative systems. Their framework is theoretical, in that it is practically impossible to conduct extensive case analysis, but for very narrow domains. It is useful however, in that it provides a formal basis for characterising the consistency, completeness and independence of a set of norms. 3.3.1 Elements of a normative problem In Alchourr ó n and Bulygin ’ s framework, a normative problem is the deontic characterisation of a set of actions U A for an agent, that is the designation of individual actions in the set as permitted, obligatory, forbidden and so on. The set of situations in which such actions may take place is called the ‘universe of discourse ’ U D : these are the situations for which the drafter or analyst of a set of norms has to cater by specifying what actions are permitted, obligatory, forbidden and so on. In other words a normative problem requires the association of situations of U D with deontically characterised actions of U A ; such deontically characterised actions are called solutions . The situations of the universe of discourse are essentially state-descriptions, that is, truth-functional compounds of the properties that hold in them. Alchourr ón and Bulygin’ s method requires the identification of a finite set of properties U P that make up situations. Such properties are intended to be the ones relevant to the normative problem and their selection plays a central role in the whole approach as we shall see in the discussion section later. Truth-functional compounds of properties of the U P define the factual range of the problem, the set U C of elementary cases. It can be shown that every situation in the universe of discourse belongs to exactly one elementary case. Put alternatively, the universe of cases U C comprises schemata for cases and partitions the individual cases of the universe of discourse in classes. To provide solutions for the situations in U D it suffices to provide solutions for the elementary cases U C . The set of solutions comprises deontically characterised truth-functional compounds of possible actions from the U A . Possible characterisations are: Obligatory (O ), prohibited ( B), optional or facultative ( F) and permitted ( P). Deontic logicians have debated on whether these notions are inter-definable and on which should be taken as primitive. Alchourró n and Bulygin take P as the primitive deontic operator and define the others as follows, where α denotes an action: • O α ≡ ∆ Pα ∧ ¬P¬α • Bα ≡ ∆ ¬Pα ∧ P¬α • Fα ≡ ∆ Pα ∧ P¬α These definitions capture some common-sense intuitions: What is obligatory is not prohibited and vice versa; a facultative act is neither prohibited nor obligatory; an act is obligatory if its complementary is prohibited. 12 The set of solutions U S to the normative problem comprises therefore expressions involving these deontic operations. The correlation of solutions with cases is done through the norms that are being examined, that is the linguistic expressions of the legislative or regulatory text. This is illustrated by the following example taken from a sample contract. The provisions concern relief from liability under Force Majeure circumstances with unnecessary detail omitted for the sake of clarity and space: (C1) The expression “ Force Majeure” shall mean any event or circumstance which is beyond the control of the Party concerned, acting or having acted as a reasonable and prudent operator, resulting in or causing the failure by such Party to perform any of its obligations under this agreement, which failure could not have been prevented or overcome by the Party. (C2) The circumstances which shall be within the definition of Force Majeure (fulfilling the requirements of clause C1) shall include but not be limited by the following: Acts of God, forces of nature, epidemic and quarantine restrictions, land-sliding, lightning, earthquakes, fire, floods, storms, tidal waves, strikes, lock-outs or other industrial disturbances, sabotage, acts of war (etc.). (C3) Notwithstanding anything in clauses C1 and C2 the following events shall not be treated as Force Majeure: [NB: List of situations that do not qualify as Force Majeure] (C4) A Party intending to seek relief under this article shall not be entitled to such relief unless such Party shall (a) as soon as practicable, but within 7 days of the day upon which the Party first knew of the failure to fulfil its obligation, notify the other Party and provide the other Party with an interim report containing all relevant information (b) within 30 days provide the other Party with a full report which shall amplify the information contained in the interim report and contain further information as the other Party may reasonably require (c) upon request give or procure access for representatives of the other Party to examine the scene of the event which gave rise to the failure and such access shall be at the expense of the Party who failed (C5) Relief under this article shall cease to be available to a Party in respect of an event of Force Majeure if it fails to take as soon as practical all necessary steps to rectify the cause of the failure. For this example our Universe of Discourse U D contains all situations in which any of the parties that have come into the agreement fail to fulfil its obligations and seeks relief from liability attributing such failure to Force Majeure. The question we seek to answer in all those situations is whether or not the party that failed to fulfil some obligation is granted relief from liability. We must choose the properties that will be included in our Universe of Properties U P and to do so we are guided by the clauses (C1)– (C5), which are relevant to the problem. From clauses (C1) — (C3) we see that the nature of the event, in which failure to perform an obligation occurs, is relevant, as some circumstances are recognised as Force Majeure whereas others do not. We can denote all circumstances that qualify as Force Majeure ones by P. From clause (C1) it also seems obvious that the conduct of the Party seeking relief is also relevant, that is whether the Party acted as a reasonable and prudent operator, and we can denote that by R. The performance of certain actions by the party seeking relief is relevant as can be seen by clause (C4) and we shall denote the property of those actions being executed as Q. Finally, rectifying the cause of a Force Majeure event is relevant to whether relief is granted by clause (C5) and S denotes this. The elementary cases to which these four properties give rise are 16. The action that is to be deontically characterised is providing relief from liability to a party due to Force Majeure, here denoted by ρ . 13 In contracts, there are at least two agents whose actions we want to characterise deontically. Deontic operators are therefore indexed by p (for the party granting relief), s (for the party seeking relief) and x (where this distinction is not important). The norms expressed by provisions (C1 – (C5) can be reformulated as follows, where each norm takes the form <solution>/<case>: (N1) O p ρ / (P, Q, R, S) (N2) Bp ρ / (¬Q) (N3) Bp ρ / (¬S) (N4) Bp ρ / (¬P) Their association with the elementary cases identified earlier is shown below: C I P Q R S N1 N2 N3 N4 C1 ++++ O p ρ C2 +++– Bp ρ C3 + + – + C 4 ++–– Bp ρ C 5 + – ++ Bp ρ C 6 + – + – Bp ρ Bp ρ C 7 + ––+ Bp ρ C 8 + ––– Bp ρ Bp ρ C 9 – +++ Bp ρ C 10 – ++– Bp ρ Bp ρ C 11 – + – + Bp ρ C 12 – + –– Bp ρ Bp ρ C 13 ––++ Bp ρ Bp ρ C 14 ––+ – Bp ρ Bp ρ Bp ρ C 15 –––+ Bp ρ Bp ρ C 16 –––– Bp ρ Bp ρ Bp ρ Table 3 Association of Elementary Cases with Solutions Solutions that appear in the same column derive from the same norm that corresponds to that column. Solutions that appear in the same row are the ones that can be derived from the system for the elementary case that corresponds to that row. A case which is not associated with any solution (i.e. no solution appears in its row) is a normative gap (for example C 3 above) . As no solution is derived for such an elementary case, no solution is provided by the system for any individual case of the universe of discourse that belongs to the class of that elementary case. A normative system with at least one normative gap is called incomplete. A system is inconsistent in a case C i if and only if there are two or more incompatible solutions associated with it; otherwise, the system is consistent. The notion of incompatibility between two or more norms is relevant to the system of deontic logic that is being used. In the example given here, two norms would be incompatible if one were prescribing an obligation for an agent to do α and the other a prohibition for the same agent to do α under the same circumstances. A system is redundant in a case C i if and only if the same solution is associated with 14 a case through two or more norms (i.e. it appears at least twice in the row associated with the case). The system of the example is redundant as can be seen for example from C 6, C 8, C 10, C 12, C 13, C 14 , C15 and C 16 . The norms of a system are said to be independent if and only if there is no case in which the system is redundant. So the system of the example is incomplete, consistent and redundant and only (N1) is independent of the other norms. As Alchourr ón and Bulygin point out, though the presence of redundant norms is undesirable, one must be careful when trying to adjust them lest removal of a norm leaves normative gaps. 3.3.2 Discussion Alchourrón and Bulygin ’ s approach offers an attractive theoretical framework within which to view normative systems and their formal properties for legal drafting. The criteria for well-formed provisions can be addressed through an analysis such as the one conducted on the example. Hence the effects of a norm, whether there is ambiguity that needs clarification, the consistency and completeness of a given set of norms can be addressed in the process of associating solutions with cases. It is not quite so easy to put their proposal to practice however and hopefully the example that was presented has already raised some issues with the reader: How are we certain that the properties chosen to define elementary cases are appropriate, or even the only appropriate ones? In the example, a simplification was made and various circumstances were grouped under P or Q. How can we be certain that we have chosen all of the relevant properties? Alchourrón and Bulygin stipulate that the choice of properties is crucial and that they must fulfil certain requirements: They must be logically independent otherwise they will give rise to logically empty cases. They must also be empirically independent otherwise they will give rise to empirically empty cases. It is possible for two properties to be logically but not empirically independent (that is, they may have a causal relation). A logically complete system is empirically complete as well so the requirement for logical independence is stronger. Properties must also be logically independent of the actions that we are trying to characterise deontically, otherwise we might get solutions that would determine deontically certain actions that are impossible to realise. Finally the set of properties chosen and the universe of discourse (the set of all situations that the system is meant to address) must be corresponding, otherwise we can no longer rely on providing solutions for elementary cases in U C and completeness, consistency and independence of the norms for U C do not necessarily entail completeness, consistency and independence of norms for the universe of discourse. A second point concerns the actual association of solutions with cases with reference to the linguistic expressions on the legislative, regulatory, or contractual text. The process itself relies on interpretation. For instance, in the example clause (C5) was taken to mean that a party is prohibited from offering relief from liability if the other party does not rectify the cause of Force Majeure. The expression “Relief under this article shall cease to be available to a Party…” however might be regarded as implying that the party seeking relief has no right (in the Hohfeldian sense [Hohfeld 15 1913]) to expect to be granted relief, that is that there is no obligation on the other party to provide it. The alternative interpretation of (C5) might therefore be Fp ρ or ¬O p ρ . A third point concerns the possible deontic characterisations for actions supported by the logic employed by Alchourrón and Bulygin: Given an action α the possible permission statements that can be formulated for it and its complement are: Pα ∧ ¬Pα Contradictory Pα ∧ P¬α Fα Pα ∧ ¬P¬α O α ¬Pα ∧ P¬α Bα or O ¬α ¬ Pα ∧ ¬P¬α Obligation to refrain from action P¬α ∧ ¬P¬α Contradictory Contradictory statements aside, Alchourr ó n and Bulygin account for obligatory actions and their dual, prohibited ones. They also account for facultative actions but not for what might seem to be their dual, “obligations to remain passive ”. What expressions of this kind essentially mean is that an agent is not responsible for an action α or alternatively that α is ultra vires for a given agent. This seems to deprive the framework from the ability to account for norms pertaining to agent responsibility. Recent systems of deontic logic do allow for this possibility as is the case in the theory of normative positions, which is discussed later. A fourth point concerns the action itself that is deontically characterised and the properties chosen the representation as it stands does not account explicitly for temporal conditions. Hence, what might be intended by (N1) could be that it is obligatory to provide relief from liability after a claim has been made and during the period in which Force Majeure circumstances obtain, rather than a temporally unqualified obligation. As regards temporally characterised norms themselves, we might want to e,stablish the consistency and completeness of them with respect to time , which would call for a different kind of analysis than the one presented here. A lengthier discussion of these issues is included in [Daskalopulu 1998] but the remarks made so far illustrate the complexity of the approach. As mentioned earlier it is practically impossible to conduct extensive case analysis but for very narrow domains; even in those cases putting the approach to practice is far from straightforward. 3.4 Normative Positions The theory of normative positions developed by Jones and Sergot [1993] and automated by Sergot [1998] is an extended version of the Kanger – Lindahl theory [Kanger 1972; Lindahl 1977]. The theory attempts to apply a combination of deontic logic and the logic of action/agency to the formalisation of Hohfeld’ s [1913] fundamental legal conceptions. The generalised theory included automated inference methods which have been implemented in computer programs intended to facilitate application of the theory to the analysis of practical problems, either for the purpose of interpretation and disambiguation of legal texts, or in the design and specification of a new set of norms. The objective is to clarify and expand an incomplete and imprecise statement of requirements 16 into a precise formal specification at some desired level of detail. The role of the system is to guide this process, ensuring overall consistency and identifying any possibilities that remain to be explored. 3.4.1 Elements of the Theory of Normative Positions Normative positions are formed by applying deontic operators to act-descriptions. The relativized monadic operator E x prefixes propositions with expressions of the form E x p read as “agent x brings it about that p ” or “agent x sees to it that p is the case ”. The operator is a success operator (that is, if x brings it about that p, then p is the case) and is closed under logical equivalence. Given a logical statement describing some state of affairs A, there are two possible fact positions: A and ¬A. From those three act-positions are constructed (cf. [Jones & Sergot 1993] for full details of the method) for a given agent α: (A1) EαA (A2) Eα¬A (A3) ¬EαA ∧ ¬Eα¬A These are mutually exclusive and jointly exhaustive. (A3) expresses the fact that an agent remains passive or neutral with respect to A. From those through a process of exhaustive generation and elimination due to logical inconsistency, the method returns seven normative one-agent act positions (which correspond to Lindahl’ s “basic types of one-agent legal positions”). P and O are operators for permission and obligation respectively and the axioms for them are those of SDL [Chellas 1980]. T1 PEαA ∧ PEα¬A ∧ P( ¬EαA ∧ ¬Eα¬A) T2 PEα A ∧ O ¬Eα¬A ∧ P( ¬EαA ∧ ¬Eα¬A) T3 PEαA ∧ PEα¬A ∧ O (E αA ∨ E α¬A) T4 O ¬EαA ∧ PEα¬A ∧ P( ¬EαA ∧ ¬Eα¬A) T5 O EαA T6 O ( ¬EαA ∧ ¬Eα¬A) T7 O Eα¬A Table 4 Normative one-agent act-positions These completely characterise an agent ’ s legal position with respect to a state of affairs. For example T1 specifies that agent α is permitted to see to it that A is the case, and he is permitted to see to it that ¬A is the case, and he is also permitted to do neither (in other words, the agent can do anything he elects with respect to A and also he can choose to remain passive). T 2 specifies that the agent is permitted to remain idle and to bring it about that A but is obliged to not bring it about that ¬A. By T3, the agent has choice with respect to bringing it about that A or that ¬A but he must act. T 6 is interesting with respect to a point made for Alchourr ó n and Bulygin ’ s analysis earlier: this requires the agent to remain passive, which as we saw is not a possibility with the deontic logic employed in Alchourrón and Bulygin ’ s framework. 17 Jones and Sergot have extended Lindahl ’ s theory to account for situations involving two agents (α and β), and this is particularly useful in contractual situations where some obligations or rights are relevant to both parties rather than one of them only. By re-naming T 1 – T7 so that the agent they refer to and the fact position they contain become explicit, two sets of one-agent act-positions are obtained, T 1 [ α;A]– T7 [ α;A] and T 1 [ β ;A]– T7 [ β ;A]. There are 49 possible conjunctions describing the legal positions of the two agents with respect to the state of affairs A, with one conjunct from the set {T 1 [ α;A], …,T 7 [ α;A]} and the other from the set {T 1 [ β ;A], …,T 7 [ β ;A]}. Of those only 35 (in Lindahl denoted as R i ) are internally consistent and constitute the space of possible legal relations that one needs to consult in interpreting or disambiguating norms. 3.4.2 Discussion To illustrate the normative positions approach to the analysis of norms, consider again an extract from the sample contract concerned with Force Majeure, introduced in section 3.3. (C4) A Party intending to seek relief under this article shall not be entitled to such relief unless such Party shall (a) as soon as practicable, but within 7 days of the day upon which the Party first knew of the failure to fulfil its obligation, notify the other Party and provide the other Party with an interim report containing all relevant information (b) within 30 days provide the other Party with a full report which shall amplify the information contained in the interim report and contain further information as the other Party may reasonably require (c) upon request give or procure access for representatives of the other Party to examine the scene of the event which gave rise to the failure and such access shall be at the expense of the Party who failed (C5) Relief under this article shall cease to be available to a Party in respect of an event of Force Majeure if it fails to take as soon as practical all necessary steps to rectify the cause of the failure. Let A denote that relief from obligations under Force Majeure circumstances is granted, B denote that a party provides an interim report within 7 days, C denote that a party provides a full report within 30 days, D denote that a party gives access to the other party and E denote that a party takes steps to rectify the cause of Force Majeure. Let the index π denote the party that provides relief from Force Majeure and σ denote the party seeking relief from Force Majeure. According to the clauses above and the one-agent act-descriptions noted earlier, the normative content of these clauses is: (N1) ( O EσB ∧ OEσC ∧ O EσD ) ∧ ( ¬ (E σB ∧ E σC ∧ E σD ) ¬ O EπA) (N2) O EσE ∧ ( ¬EσE ¬ O EπA) The expression “A Party…shall not be entitled …” is captured by ¬O EπA, conforming to the Hohfeldian connection between right and duty (here right is taken to be entitlement and duty is taken to be obligation). The consequent of both norms could be different, depending on what the intended interpretation is. In the version given above, agent π is not obliged to offer relief from liability. Other possible interpretations might be: 18 • PEπA ∧ PEπ¬A ∧ O (E πA ∨ E π¬A): agent π is permitted to see to it that relief is granted, permitted to see to it that relief is not granted but obliged to see to it that relief is either granted or not granted; • PEπA ∧ PEπ¬A ∧ P( ¬EπA ∧ ¬Eπ¬A): agent π is permitted to do nothing about the claim (which seems unlikely as an intended interpretation but the text of the provision alone does not rule it out) • O Eπ¬A: agent π is obliged to see to it that relief from liability is not granted. There are two points worth discussing here. First in the example it is not clear whether a party ceases to be entitled to relief from liability by not complying with any or all of the three conditions set out in clause (C4). This is where Allen is right about ambiguity arising from the relations between sentences. If the conditions (a) – (c) are implicitly conjoined (which seems reasonable to assume) then (N1) above is the intended interpretation. Second, it might be argued that the party seeking relief is not strictly speaking obliged to see to it that A, B, C, and D are the case. That is, sub-clauses (a) – (c) might be better conceived as procedural steps that a party seeking relief from liability due to Force Majeure needs to complete in order for it to be granted such relief. Such a reading of the clauses would entail that a party performing these steps has the power to bring about a state of affairs in which it is granted relief from liability due to Force Majeure. Power here is meant in the Hohfeldian sense, that is, it refers to the ability to create legal relations, in this instance the obligation on the other party to grant relief. Strictly speaking granting relief from liability itself is a power relation. That is, the party granting relief from liability is establishing a state of affairs in which the relieved party is not bound by its obligations. If a party seeking relief from liability performs (a)– (c), then the other party is obliged to exercise that power. The main benefit of the theory of normative positions is therefore that it brings to the foreground questions about intended interpretation, structural ambiguity, the precise nature of legal notions (whether they are primary or concern other legal relations) and so on. It is a more powerful tool in addressing interpretation questions and in disambiguating between legal notions than any of the other approaches discussed here and it can be integrated with the theoretical framework of case analysis to address normative consistency, completeness and independence. In a similar manner to Alchourr ón and Bulygin ’ s framework, elementary cases are associated with normative positions for agents. The definitions for completeness and independence remain unaltered. The definition for consistency requires some adjustment: A system is inconsistent in a case C i if and only if there are two or more incompatible norms associated with it; otherwise, the system is consistent. For a given agent α and a fact position A, two norms are inconsistent if they are both members of the set {T 1 [ α;A], …,T 7 [ α;A]}. For norms concerning two agents, two norms are inconsistent if they are both members of the set of norms R i . Where norms concern two agents but different fact positions, that is one is a member of the set {T 1 [ α;A], …,T 7 [ α;A]} and the other a member of the set {T 1 [ β ;B], …,T 7 [ β ;B]} their consistency depends on the relation, if any, between A and B. 19 Finally, the representation as it stands does not allow for temporally qualified normative statements. These are very frequently encountered in contracts where parties have obligations that only arise within specific times (whether these are in absolute or relevant terms). Such an extension to the representation would yield different definitions for consistency and completeness of norms. 4 Conclusions This paper reviews four approaches that might be employed for the representation of contractual contents at the micro-level, that is, at the level of detailed individual provisions. The sample contracts used for this research indicate that contractual provisions are of varying nature and serve different purposes. Some criteria for well-formed provisions are raised and they can be addressed in different ways, depending on the nature of the provision to which they apply. Logic Programming representations offer the benefit of executable specifications that drafters may employ to determine whether a set of provisions have the desired effect. If we were aware of all possible circumstances that might arise and executed them for the corresponding sets of data, we would be able to establish completeness and similarly by querying the representation appropriately we could determine whether there is inconsistency. To determine completeness and consistency of temporal conditions of provisions some sort of temporal algebra is required, such as Allen ’s [1984] for example. Where logic programming representations fall short is in accounting adequately for legal notions such as duty, right, power and so on. Though prescriptive provisions can be represented in the same way as qualification norms for some purposes, such representation conflates the distinction between the actual and the ideal. Consequently, if the effects of prescriptive provisions are of interest, especially in cases of violation, and if it is their consistency that one wants to establish, some form of deontic logic is required. The analysis of norms relative to the particular system of deontic logic adopted merits a lengthier discussion than can be accommodated here. Much of the literature in deontic logic is concerned with the analysis of deontic conditionals and contrary-to-duty structures [Chisholm 1963], in which an agent ’ s obligation to bring about A is conditional upon his violation of some other obligation. Such structures are very common in contracts, especially in relation to early termination of an agreement. As Jones and Sergot [1993] point out, even deciding what detachment principles to accept for deontic conditionals raises non-trivial issues that need to be addressed. There is a significant amount of recent research in the representation of deontic conditionals and contrary-to-duty structures that needs to be put to the test in the domain of legal contracts (for example [Alchourr ó n 1993; Jones & Pö rn 1991; Prakken & Sergot 1996; Prakken & Sergot 1997]). Legal notions are explicitly defined in Allen and Saxon’ s normalised language for legal drafting, but their system does not seem to offer inferencing facilities that would be useful in establishing the effects of prescriptions. Their proposed language is specifically aimed at identifying ambiguity, especially the kind that arises by the use of connectives in natural language to relate segments of text and by the conflation of certain legal notions, such as right, privilege, power. The theory of normative positions on the other hand can assist in disambiguating prescriptions, in establishing the effect of given legal relations and in determining consistency of a set of norms. Alchourr ó n and 20 Bulygin’s work provides a framework for the formal explication of norm consistency, completeness and independence, though the underlying deontic logic is not as expressive as that of normative positions. Acknowledgements: I am grateful to Marek Sergot of Imperial College, London for numerous inspiring discussions over the last few years and for his endless patience and support. A lot of the observations made in this paper arise from Marek ’ s ideas though any omissions or possible misconceptions are entirely my own. Thanks are also due to Chris Reed who read and commented on drafts of this paper, and to John Salt for bringing the term ‘ ultra vires’ to my attention. 5 References Alchourrón, C. E. (1993). 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