Combining individually inconsistent prioritized knowledge bases

It is well accepted that inconsistency may exist in a database system or an intelligent information system (Benferhat et al. 1993a; 1993b; 1997b; 1998; Benferhat & Kaci 2003; Elvang-Gøransson & Hunter 1995; Gabbay & Hunter 1991; Lin 1994; Priest et al. 1989; Priest 2001). Inconsistency can either appear in the given knowledge bases or as a result of combination or revision. In this paper, we will propose two different methods to combine individually inconsistent possibilistic knowledge bases. The first method, called an argument-based method, is a generalization of the merging method introduced in (Benferhat & Kaci 2003). When the knowledge bases to be merged are self-consistent, this method coincides with the original one. The second method, called a multiple-operator based method, combines the consistent and the conflict information using different operators. This method is more reasonable than the argument-based method because it differentiates the consistent and conflict information.