Takashi Kanai and Susumu Kunifuji

Abstract:
In this paper, we propose a new legal reasoning system using abductive logic programming (ALP). The system can deal with ambiguities of described facts and exceptions which is not described in relevant articles. In addition, the goal, queried to a legal reasoning system, differs in compliance with whether the user is a plaintiff or defendant. In usual deductive legal reasoning systems, there are two major problems in treating legal arguments. One is that legal facts usually have ambiguities, and the other is that two conflicting conclusions must be derived from one knowledge base, depending on whether a plaintiff of defendant is involved. To overcome these difficulties, abductive logic programming is used in our legal reasoning system, which can deal with implicit exceptions and generate presumptions according to the user's needs.

Keywords: Abduction, Legal reasoning, Hypothetical reasoning, CISG