Formalising Jurisprudence: Festschrift for Hajime Yoshino

Von Friedrich Lachmayer, Erich Schweighofer, Michal Araszkiewicz und Marijan Pavcnik

Hajime Yoshino ist seit den Siebzigerjahren ein maßgeblicher Protagonist der Rechtslogik und der Rechtsinformatik in Japan. Der Gelehrtencommunity um Herbert Fiedler, Arthur Kaufmann, Ulrich Klug, Lothar Philipps, Jürgen Rödig, Ilmar Tammelo und Ota Weinberger entstammend, hat er sich unermüdlich für die Anwendung der Logik in der Rechtswissenschaft eingesetzt und damit auch den Weg für die Rechtsinformatik mitbereitet. Sein Anliegen, das er in der "Logischen Jurisprudenz" zusammengefasst hat, ist Auftrag und Zeichen, die formalen Wurzeln der Rechtswissenschaft im Übergangsfeld zur Rechtsinformatik weiterhin zu verstärken und auszubauen.

Professor Hajime Yoshino ist eine angenehme und humorvolle Persönlichkeit. Es ist ein Privilegium, ihn treffen zu können. Er regt die Diskussionen an und wirkt integrativ.
Im Zuge der Gestaltung dieses Sammelbandes wurde erneut deutlich, dass es in der wissenschaftlichen Praxis nicht nur um den Kernbereich der Anwendung der formalen Logik geht, sondern dass das Wort "Formalisierung" ein weiteres Feld beschreibt, das – der Avantgarde zugeordnet – durch explizite Strukturierungen eine intellektuelle Durchdringung des Rechtes und seines Umfeldes aufbereitet. Die Vielzahl der in diesem Sammelband behandelten Themen gruppiert sich in unterschiedlicher Intensität um Yoshinos Anliegen einer Rechtswissenschaft, in welcher der Logik und dem formalen Denken ein grundlegender Stellenwert zukommt.

• Sprache: Deutsch
• Herausgeber: Editions Weblaw
• Erscheinungsdatum: 28. Feb. 2019
• ISBN: 9783906940748

Buchvorschau

Pavčnik

Kevin D. Ashley – Legal Informatics and the CISG

Legal Informatics and the CISG

Kevin D. Ashley[1]

1. Introduction

Professor Hajime Yoshino has long taken an interest in The United Nations Convention on Contracts for the International Sale of Goods. The CISG (or the Vienna Convention) is a treaty that sets up a uniform international sales law. In the 1990s, he sponsored a series of international workshops on Legal Expert Systems for the CISG. During the intervening years, the CISG has been a centerpiece in his scholarly work in:

–  proposing a formal logical model of the CISG to assist with the problem of applying the treaty within and across legal systems, cultures, and languages,

–  illustrating the need for meta-reasoning about the validity of legal sentences, for modeling the Convention’s open-textured legal concepts using, for instance, fuzzy logic, and for logically modeling temporal reasoning,

–  demonstrating a legal expert system which, as it analyzes sales contract problems, reasons about the validity of legal sentences describing the parties’ obligations and rights and generates the changes in their legal relations,

–  using such a legal expert system as a pedagogical tool for teaching structured legal reasoning and a context for inculcating creative legal thinking.

In the meantime, more recent developments in the fields of legal informatics and AI and Law have focused on computationally modeling legal argument in more empirically descriptive ways and on applying techniques for text analytics and argument mining. These developments suggest how to improve legal information resources serving the community of CISG practitioners.

This paper examines the current technological approaches to modeling the CISG for purposes of legal information retrieval, relates them to the intellectual challenges Prof. Yoshino posed and the problems he addressed in his longtime focus on the CISG, and identifies areas for future work that might someday connect aspects of his models to the relevant legal texts.

The next section introduces the CISG, and section 3 surveys Professor Yoshino’s work with the Convention. Section 4 addresses some new research directions that could build on his introduction of and work on the CISG, followed by some conclusions in section 5.

2. Introducing the CISG to the AI and Law Community

According to Professor HARRY FLECHTNER (2009), a noted contract law scholar, «The United Nations Convention on Contracts for the International Sale of Goods (CISG) has been recognized as the most successful attempt to unify a broad area of commercial law at the international level.» It aims to increase international trade by providing a set of «substantive rules governing the rights and obligations of parties to international sales contracts.» With only eleven initial contracting states in 1988 when it first entered into force, the CISG has now been ratified by 89 states.

Among the CISG’s significant provisions, Flechtner includes those that address:

–  Interpretation of the parties’ agreement…;

–  The features, duration and revocability of offers;

–  The manner, timing and effectiveness of acceptances of offers;

–  The effect of attempts to add or change terms in an acceptance;

–  Modifications to international sales contracts;

–  The seller’s obligations with respect to the quality of the goods as well as the time and place for delivery;

–  The place and date for payment;

–  The buyer’s obligations to take delivery, to examine delivered goods, and to give notice of any claimed lack of conformity;

–  The buyer’s remedies for breach of contract by the seller…;

–  The seller’s remedies for breach of contract by the buyer…;

–  Passing of risk in the goods sold;

–  Anticipatory breach of contract…;

–  Exemption from liability for failure to perform, including force majeure;

–  Obligations to preserve goods that are to be sent or returned to the other party. (Flechtner 2009)

«The primary goal [of the drafters of the CISG] was to create uniformity in the rules for international sales, in order to supplant the complex and difficult-to-predict system that subjected international sales to the varying provisions of national sales laws.» (FLECHTNER 1998).

Professor Yoshino introduced the CISG to the field of Artificial Intelligence and Law in the early 1990’s in a series of four workshops and a number of publications. The CISG’s goal of a uniform international law of contracts may have been the reason why. Formalizing legal knowledge and inference in terms of logic has been a central theme of his career:

Typically, natural languages are used for expressing legal knowledge. Hence, if we want to formalize inferences with legal knowledge, we believe it would be better to use a formal language which has the ability to translate sentences expressed by a natural language correctly. (Yoshino 1997)

To this end, Professor Yoshino developed a Compound Predicate Formula (CPF) language and used it to translate CISG rules concerning the manner, timing and effectiveness of acceptances of offers into formal logical propositions that could be compiled.

One topic of discussion at the CISG Workshops was the relationship between a formal representation and uniformity of interpretation. This translation of the CISG’s rules into a formal language promised, among other things, to help achieve uniformity of interpretation of those rules, since, arguably, it could be assumed that the same formal propositions would underlie the various official language versions of the treaty. The formalization could serve as a kind of interlingua, which if it existed, would support uniformity in interpreting a treaty like the CISG. Alternatively, if the formal interlingua did not exist, it raised interesting questions of how and why the formal representations of the different language versions of the treaty would differ.

As noted, the CISG treaty was intended to promote uniformity in international sales law. Inevitably, as an international treaty, the CISG represents a compromise with multiple ambiguous formulations, vague terms and issues left for courts to address. Beyond that,

[t]he idea that the Convention comprises a set of uniform words--a single text describing a single set of rules equally applicable to all transactions within the scope of the CISG--turns out not to be strictly accurate. … [T}he Convention … is not … a single uniform text, but rather … a dizzying variety of texts. … [T]he very words comprising the Convention's rules will vary, often quite significantly, depending on: (1) the countries in which the parties to a CISG-governed transaction are located, and (2) the language of the tribunal resolving disputes about the transaction. This phenomenon results from the different language versions in which the Convention's sales rules are embodied, and the declarations or reservations made by various contracting states when they ratified the CISG. (FLECHTNER 1998, p. 189)

In addition, the treaty is not administered centrally. Multiple national courts have applied the treaty in its six official language versions (i.e., Arabic, Chinese, English, French, Russian, and Spanish) and according to their differing legal methodologies: civil law, common law, or using hybrid international interpretive techniques.

3. Professor Yoshino’s Work on the CISG

Professor Yoshino’s work on the CISG demonstrates some key themes of his AI and Law work: the goal of systematizing the law, the need for meta-reasoning about the validity of legal sentences, and the need for a legal expert system that performed such meta-reasoning. In (2011), Professor Yoshino laid out the logical structure of a system for reasoning about the duty relations that exist in a concrete legal problem and the legal rules that can be applied to decide it. In this framework, meta-sentences describe the validity of legal sentences; they determine if a legal rule is true and is applicable for solving the problem.

Problems involving the CISG provided a nice context for illustrating this meta-legal reasoning «from contracts through contract laws, constitutions and conventions up to basic legal rules.» (YOSHINO 2011) His papers illustrated detailed analyses of several variations of a contracts problem:

On April 1, a New York manufacturer, A (Anzai), dispatched to the Hamburg branch of a Japanese trading company, gives B (Bernard), a letter containing the following proposal: A will sell B a set of agricultural machines; the price of the machinery is $50,000; A will deliver the machinery to B by May 10; B must pay A the price of the machinery by May 20; the machinery will be transported by an American freight vessel. (2) The proposal reached B's letter box on April 8. (3) On April 9, B telephoned A and said, «I accept your offer». (4) A delivered the agricultural machinery to an American freight vessel at the port of New York on May 1. (5) The machinery was delivered to B's Hamburg branch on May 28. B examined the machinery on May 30. (6) B paid A $50'000 on May 31. (7) On August 10, the machinery malfunctioned because of a defective gear. (8) B notified A of the malfunction immediately. (9) On September 1, buyer B required seller A to repair the lack of conformity of goods by repair by October 1. (10) A did not repair the defect of the machine by October 1. (11) On October 10, B declared the contract void. (YOSHINO 2012)

The goal of his legal expert system (LES) was to answer such questions as, «What kind of legal relations exist between Anzai and Bernard on the basis of the facts of the case at the following time points? April 5, April 15, May 15, June 5, August 15, September 15, October 5, November 15, and December 15.» For instance, it should be able to deduce that the proposition, «Anzai must repair the machine for Bernard,» is valid at time September 15th and to provide a proof in support of its answer.

3.1   Meta Legal Reasoning

Professor Yoshino proposed that these legal meta-rule sentences filled in certain important gaps in a code of law like the CISG. For instance, the «most fundamental of legal meta-rule sentences» stated that,

[r0] A legal sentence is valid at time T, if and only if the legal sentence becomes valid at time T1 before T & it is not the case that the sentence becomes null at time T2 before T.

Professor Yoshino states,

This legal meta-rule sentence is not found in any positive law code but implicitly presupposed in every law code. Whenever a legal sentence is applied, this rule sentence is to be applied to decide whether the legal sentence is valid. (2012)

Another legal meta-rule sentence fills in a gap in legal relations between conferring a right and imposing a duty:

[3aa2] A legal sentence «X has an obligation to do Z at time T1» becomes valid at time T, if Y exercises the right to require X to do Z at time T1 at time T & the legal sentence «Y has a right to require X to do Z at time T1» is valid at time T.

Thus, any time a substantive legal rule in the CISG was applied, such as

[Article 46 (3)] If the goods do not conform with the contract, the buyer may require the seller to remedy the lack of conformity by repair….,

r0 would be invoked along with some helper legal meta-rule sentences to prove its validity as part of a CISG which is valid as a whole, and [3aa2] would help prove the validity of the seller’s obligation on September 15 to repair the machine.

3.2   Temporal Legal Reasoning

The references to time variables in these two legal meta-rule sentences suggest why Professor Yoshino pursued AI techniques for modeling temporal reasoning. (VILA & YOSHINO 1998) presents LTR, a time logic adapted to some of the requirements of legal reasoning. Temporal incidence predicates (TIPs) were defined such as holds, occurs, holds_​at, holds_​on, and applied to represent various provisions of the CISG dealing with offer and acceptance. Given a formalized representation of the facts in a problem like the Anzai scenario, the LTR formalization could answer a query, «Is the contract concluded?» as «YES, as of April 15» by generating a map-like representation of the events and provide an explanation in terms of the rules that fired. LTR did not address tasks that involve meta-reasoning about the validity of statutes and laws over time, which was the focus of future work in AI and Law. See, e.g. (PALMIRANI, 2011). Professor Yoshino’s work on CISG is one of the few bodies of work to address modeling temporal reasoning in law.

3.3   How Complete a Formalization is Enough?

Despite the complexity in Professor Yoshino’s examples of the proofs in which meta legal reasoning establishes the validity of a substantive rule of the CISG from the validity of the Convention as a whole, it is interesting to consider what they do not address. The examples did not address all the issues that may arise concerning whether the CISG applies to the transaction in question, including some issues that are more likely to be contested than the validity of the Convention as a whole. For instance, according to Article 1(1)(a), the CISG:

applies to contracts of sale of goods between parties whose places of business are in different States: (a) when the States are Contracting States; or (b) when the rules of private international law lead to the application of the law of a Contracting State.

Whether the States are Contracting States for purposes of this provision raises issues about whether they have elected to be bound to certain provisions. Moreover,

even where all requirements for the applicability of the CISG are met, the CISG does not necessarily have to apply….» [A]rticle 6 allows the parties to opt-out of the CISG or portions of it …. The exclusion can be express or implied …, total or partial. To exclude the Convention ex article 6, there must be an agreement between the parties …. Article 8 identifies interpretive criteria to be taken into account to determine whether there is such an agreement. Article 9 lays down rules on trade usages and course of dealing, which must also be taken into account to determine whether the parties intended to exclude the CISG. (FERRARI 1996)

This is not to criticize Professor Yoshino for oversimplifying or leaving out some necessary consideration. Surely, he would jump at the chance to apply his formal methods to any issues of validity raised by each of these additional provisions. Rather, it is to question whether he has attempted to include too much, that is, to question the practicality of his goal of developing a formal systematization of law, at least to the extent it aims to be complete. While the validity of any and every provision could be at issue, frequently it is not contested; the advocates are presumed to accept the validity of legal authorities like the CISG unless they expressly contest it. Presumably, a system should not generate proofs of every possible issue but focus on those issues that are contested or those, which, given the facts of the problem, can reasonably be contested and for which a system could construct reasonable arguments.

3.4   Case-based Reasoning and Argument

Two trends in AI and Law addressed this kind of problem of selection, case-based reasoning and the development of computational models of legal argument. Historically, they developed in that order, but today, CBR is treated as one in a number of components of a computational model of legal argument, as is logical deduction from a legal rule. The need to make or respond to an argument leads a program via critical questions or other control mechanisms to discover the reasonable grounds presented in the fact situation for developing a response. See (ASHLEY 2017, Ch. 5).

Professor Yoshino’s work applying fuzzy logic to the CISG reflected both of these trends. The Fuzzy Legal Expert System, FLES, was intended to make case-based arguments concerning open-textured terms in the CISG such as «sufficiently definite,» as in «A proposal is sufficiently definite if it indicates the goods and expressly or implicitly fixes or makes provision for determining the quantity and the price.» Article 14. (HIROTA, ET AL. 2000) Professor Yoshino and his co-authors had developed a case-base of eight CISG decisions and factors concerning prices for goods such as whether there is a market or commercial substitute for a component. (MINGQIANG, ET AL. 1998) Factors are stereotypical patterns of fact that tend to strengthen or weaken a side’s argument in support of a claim or issue. See (ASHLEY 2017, Ch. 3) FLES invoked fuzzy logic to assess the similarity of cases to a current fact situation and supported and responded to claims resolving the ambiguous term’s application.

3.5   Educating Creative Legal Minds

FLES was intended to serve as an educational system for teaching law students argumentation skills. Its predecessor legal expert systems, especially LES-5, also played a role in legal education, an important focus of Yoshino’s work on the CISG.

The input to the program is a formalization of the facts of the Anzai problem above. The program outputs a kind of time map of the legal relations among the buyer (Bernard) and seller (Anzai) in the above problem at various points of time during which a contract becomes effective, the seller is obligated to deliver the goods to buyer by May 10, seller delivers the goods, the buyer is obligated to pay the price to seller by May 20, trouble occurs, the buyer may require seller to remedy the lack of conformity of the goods by repair, the buyer exercises a claim to repair, etc. At each point the program specifies the correlative rights and obligations of the parties and can provide a justification in terms of the legal rules of the CISG and the legal meta-rule sentences like [3aa2] above.

When I first saw the output of LES-5 (or one of its predecessors) I was struck with the way in which it visually indicated the various successive legal states of affairs associated with the life of a particular sales contract under the CISG. The utility of such a system for teaching law students about contract law was immediately apparent. The program’s outputs are a window through which students can perceive not only the CISG’s substantive provisions of contract law such as offer and acceptance but also the often unstated supplemental rules of statutory interpretation, the legal meta-rule sentences, that, in Professor Yoshino’s view, are an all-important component of a formalization of legal reasoning, and thus a necessary element of understanding legal reasoning. The gaps in legal reasoning, the presumed knowledge that might otherwise elude a student’s attention, are thus made explicit.

Formalization and systematization are key in Professor Yoshino’s thought on educating creative legal minds.

Deductive reasoning in law is not a given system. To systematize the law is not to recognize a given system, but to create a system. People who attempt to understand the law have to create it themselves. Actual legal regulations in themselves do not compose a strict system. People who apply and interpret the law systematize it themselves. The systematization of law is creative legal thought. (YOSHINO & SAKURAI 2005)

LES-5 provided students examples of a systematization of parts of the CISG. Then, through a series of problems in which components of the systematization were intentionally omitted, students were invited to come up with their own components to fill in the gaps. After all, filling in the gaps of a law code with legal meta-rule sentences was the way in which Professor Yoshino’s creative legal mind expressed itself, and it is natural that he would seek to enable his law students to learn to do the same. Query whether any AI and Law scholar from a civil law jurisdiction has done more than Professor Yoshino to model the kinds of interpretive rules that play such an important role in civil law reasoning.

4. Future Research on the CISG

Having briefly surveyed the arc of Professor Yoshino’s CISG research, it is interesting to consider the kinds of research challenges this convention may still hold for a new generation of AI and Law researchers. Legal expert systems are still an important component of AI and Law, but they are used primarily for document assembly, business compliance, and directing clients to the right human experts for their problems. As noted, recent developments in the fields of legal informatics and AI and Law have focused on applying text analytics and argument mining to extract semantic information from legal texts and on modeling legal arguments in more empirically descriptive ways.

4.1   Applying Legal Text Analytics to the CISG

Text analytics or text mining involves discovering knowledge using linguistic, statistical, and machine learning techniques to model some information content in text archives. Legal text analytics involves archives of legal texts including regulatory texts (e.g., statutes, treaties, and regulations), case decisions, and contracts. Argument mining involves the text analytic discovery of argument-related information. Machine learning (ML) refers to programs that use statistical means to induce or «learn» models from data. The resulting models can predict outcome classifications for a new instance or case. See (ASHLEY 2017).

Today, there are more than 3,000 cases involving the CISG and 10,000 case annotations.[2] A CISG corpus of electronic versions of the texts of these cases, in the original language and English translations, is readily available from public sources. While the Pace Law School’s CISG Database is an excellent resource, new approaches to legal information retrieval could dramatically improve the accessibility of these materials beyond the use of keyword searches and indexing.

Frequently in CISG cases, a complaining party brings suit against a responding party for breach of contract, and either succeeds in showing that the facts comply with the CISG’s requirements for recovery or not. When a number of court decisions focus on the same CISG provisions and present factually similar scenarios, the courts sometimes reach inconsistent results, based on inconsistent interpretations of the CISG. An interesting challenge for AI and Law researchers would be to detect such inconsistencies in treaty interpretation automatically.

An initial step would be to improve legal information retrieval resources serving the community of CISG practitioners by enabling them automatically to identify and retrieve cases that deal with particular issues, arguments, and results. One could assemble a corpus of CISG case texts and develop a program to determine the legal requirements at issue in a case, the court’s conclusions regarding the issues, the types of arguments employed, and whether other courts have addressed the same issues in factually similar circumstances but reached different outcomes (or the same result but for different reasons). The main hypothesis to test would be that a program can detect in the corpus of CISG texts, with acceptable levels of classification accuracy and confidence, the legal requirements, conclusions, argument types, and instances of differing legal results or treaty interpretations.

An important step in this process would be to develop a rule tree, that is a tree of authoritative rule conditions for applying the CISG’s substantive contract provisions. (WALKER, ET AL. 2011) This process would be similar to what Professor Yoshino and his colleagues have already done: manually analyzing the statutory and treaty provisions in order to encode the legal rules. (see, e.g., YOSHINO 1997) An interesting question will be the extent to which the rule tree would need to include legal meta-rules of the types Professor Yoshino identified. The rule tree is not intended to serve as a support for deductive reasoning but as an index into the legal issues actually addressed in the decisions. In studying the CISG cases, citation networks could identify the most influential precedents and one could examine these to identify legal meta-rules that the courts have expressly applied.

Then, the goal would be to find ways in which a program could automatically detect those legal issues that a decision addresses and where they connect to the rule tree. Citations will also play a role in this detection, but machine learning and rules for detecting standard formulations and functional abstractions of legal provisions will also probably assist. The goal is to annotate the case texts in syntactic and domain general semantic terms and in terms of the evidential reasoning chains from facts to legal conclusions (WALKER, et al. 2011) and of factors and other functional and magnitude/​certainty indicators. Professor Yoshino’s work on FLES (MINGQIANG, ET AL. 1998; HIROTA, ET AL. 2000) is one indication that factors can be useful in the CISG domain on such issues as whether quantity and price are «sufficiently definite».

Since they deal with contracts and contract law, CISG cases present an opportunity to examine the contractual provisions and arguments that courts have considered in applying the CISG and to attempt to model them computationally, something that has not been attempted in AI and Law since the 1990s. Today, text analytic advances in analyzing contracts may enable researchers to gain some traction on modeling such arguments, for example, where courts interpret contractual language attempting to opt out of the CISG.

Implementing and integrating these kinds of annotations would require defining a formal system of layered annotation types using, for example, the UIMA framework.[3] The type system, a kind of ontology for text analysis of legal decisions and arguments concerning the CISG, would define the required annotations to represent terms (including functional terms from the CISG) syntax, semantics, legal argumentation and evidential reasoning and how these layered annotations are linked together as the different tools annotate a case text.[4] The formal type system would be used to combine human annotation (a gold standard) with the outputs of automatic components, such as pattern matching with heuristic rules or statistically-trained language models. LUIMA, a legal unstructured information management architecture and tools, adapt UIMA to some of the requirements of a legal domain. (GRABMAIR 2011).

The program’s annotations could be evaluated against a ground truth: the legal cases provide an objective record of who won, and often, for each issue, one can objectively determine who won that issue, why, or why not. In cross validation experiments, a standard procedure for evaluating a machine learning program, these cases provide a basis for objectively measuring performance and effectiveness in detection. See (ASHLEY 2017, Ch. 10) Since examples of inconsistent judicial decisions concerning the CISG attract legal scholarly interest, the secondary literature also provides a basis for identifying cases with inconsistent interpretations.

4.2   The Multi-language CISG

A continuing focus on CISG research could also present an opportunity to address issues of translation in AI and Law. The original texts of both the CISG provisions and cases have been published in languages other than English. Google Translate can translate texts of CISG provisions from one language to another. Consider the example below of French and English versions of Article 46(3). The example shows a translation of the official French version of the above-cited Article 46(3) into English (e) and of the official English version into French (c) and back into English (d). Comparison of the English texts (a), (d), and (e) demonstrates serviceable translations but some concepts appear to wander. A «request for repair» in (a) has become a «claim for compensation» in (d) and «The remedy» in (e). While a human reader of (e) may recognize that «The remedy» refers to the request for repair in the previous sentence, a «request for repair» has a different meaning than a «claim for compensation». In addition, the concept of «notice» in (a) and (d) becomes a «denunciation» in (e).

Article 46(3)

(a) Official English Text: If the goods do not conform with the contract, the buyer may require the seller to remedy the lack of conformity by repair, unless this is unreasonable having regard to all the circumstances. A request for repair must be made either in conjunction with notice given under article 39 or within a reasonable time thereafter.

(b) Official French Text: Si les marchandises ne sont pas conformes au contrat, l'acheteur peut exiger du vendeur qu'il répare le défaut de conformité, à moins que cela ne soit déraisonnable compte tenu de toutes les circonstances. La réparation doit être demandée au moment de la dénonciation du défaut de conformité faite conformément à l'article 39 ou dans un délai raisonnable à compte de cette dénonciation.

(c) Google Translate Version of (a) into French: Si les marchandises ne sont pas conformes au contrat, l'acheteur peut exiger du vendeur qu'il remédie au défaut de conformité par la réparation, sauf si cela est déraisonnable compte tenu de toutes les circonstances. Une demande de réparation doit être faite conjointement avec un avis donné en vertu de l'article 39 ou dans un délai raisonnable par la suite.

(d) Google Translate Version of (c) back into English: If the goods are not in conformity with the contract, the buyer may require the seller to remedy the lack of conformity by the repair, unless this is unreasonable in the light of all the circumstances. A claim for compensation must be made in conjunction with a notice given under section 39 or within a reasonable time thereafter.

(e) Google Translate Version of (b) into English: If the goods are not in conformity with the contract, the buyer may require the seller to repair the lack of conformity, unless this is unreasonable having regard to all the circumstances. The remedy must be requested at the time of the denunciation of the lack of conformity made in accordance with Article 39 or within a reasonable time after the denunciation.

Recently, there has been interest in an interlingua of universal «concepts» that may emerge from Google’s multilingual Neural Machine Translation (NMT) (JOHNSON, ET AL. 2016). Although this interlingua is quite different from Professor Yoshino’s suggestion of a uniform logical formulation underlying the CISG and its language versions, it begs the question of whether translation of legal treaties requires applying more knowledge of the meaning of legal terms, a question that his CISG Workshops raised.

5. Conclusions

In introducing the field of AI and Law to the CISG, The United Nations Convention on Contracts for the International Sale of Goods, Professor Hajime Yoshino substantially enriched the field’s domain of discourse for many years. His long-standing interest in the Convention produced formal logical models of the CISG and legal expert systems that demonstrate the need for meta-reasoning to interpret the validity and meaning of a legal code and that introduce law students to creative legal thinking by showing them how to develop such formalizations.

This Festschrift in Professor Yoshino’s honor should be an occasion for the field to consider how more recent developments in the fields of legal informatics and AI and Law, focusing on computationally modeling legal arguments in actual cases and on applying techniques for text analytics and argument mining, can improve legal information resources serving the community of CISG practitioners. These developments may someday connect aspects of his models to the actual legal texts of the treaty and the cases interpreting it.

6. References

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FLECHTNER, H. (1998). The Several Texts of the CISG in a Decentralized System: Observations on Translations, Reservations and other Challenges to the Uniformity Principle in Article 7(1), 17 Journal of Law and Commerce (1998) 187–217

FLECHTNER, H. (2009). Introductory Note, United Nations Convention on Contracts for the International Sale of Goods http://​legal.un.org/​avl/​ha/​ccisg/​ccisg.html

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Katie Atkinson / Trevor Bench-Capon – The Roles of Dimensions and Values in Legal CBR

The Roles of Dimensions and Values in Legal CBR

Katie Atkinson / Trevor Bench-Capon[5]

Keywords: legal case based reasoning, dimensions, factors, values

Abstract: In this