SHYSTER and the Authorization of Copyright Infringement

The SHYSTER project is concerned with the development of a hybrid legal expert system: one which uses rule-based techniques to represent statute law and case-based techniques to represent case law. A prototype has been developed, implementing the case-based part of SHYSTER. This prototype allows a legal expert to specify an area of case law using a specially-developed case law speci cation language. The model of legal reasoning which has been adopted for the development of SHYSTER is explained, and the operation of the prototype is illustrated by example. An area of case law (the meaning of \authorization" in the Copyright Act) is speci ed, and SHYSTER is made to generate opinions about real cases on the basis of that speci cation. SHYSTER's legal opinions are compared with the actual judgments in those cases. SHYSTER's case-based system performs well in two quite di erent legal domains, suggesting that SHYSTER's approach to case law may prove successful in other areas of law. Avenues of future research are identi ed, and the manner in which SHYSTER's case-based system will be linked with a rule-based system to form a hybrid legal expert system is explained. CR