Lawrence J. Henschen, Hyung-Sik Park
This paper presents several basic results on compiling indefinite and GCWA (Generalized Closed World Assumption) inference in IDDB (Indefinite Dedutive Databases). We do not allow function symbols, but do allow non-Horn clauses. Further, although the GCWA is used to derive negative assumptions, we do also allow negative clauses to occur explicitly. We show a fundamental relationship between indefiniteness and indefinite inference. We consider three representation alternatives to separate the CDB (Clausa1 DB) from the RDB (Relationa1 DB). We present the basic ideas for compiling indefinite and GCWA inference on CDB and evaluating it through the RDB. Finally, we introduce decomposition theorems to evaluate disjunctive and conjunctive queries.