ʊ-resolution and hybrid knowledge bases

Hybrid knowledge bases (HKBs) (Lu, Nerode, and Subrahmanian, IEEE Trans. Knowledge Data Eng. 8 (5) (1996) 793) were developed to provide formal models for the mediation of data and knowledge bases (Wiederhold, IEEE Comput. (1992) 38; Proceedings of the ACM SIGMOD Conference on Management of Data, 1993, p. 434). They are based on generalized annotated logic programming (Kifer and Subrahmanian, J. Logic Programming 12 (1992) 335) and employ an inference mechanism—HKB-resolution—that is considerably simpler than others that have been proposed for generalized annotated logic programming. In this paper HKB-resolution is shown to be a special case of the inference rule ℧-resolution. This rule is formally defined, and various computational properties of it are examined.