Splitting a Logic Program 论文

详细信息

发表期刊/会议

The MIT Press eBooks

发表日期

1994-01-01

发表年份

1994

摘要

In many cases, a logic program can be divided into two parts, so that one of them, the "bottom" part, does not refer to the predicates defined in the "top" part. The "bottom" rules can be used then for the evaluation of the predicates that they define, and the computed values can be used to simplify the "top" definitions. We discuss this idea of splitting a program in the context of the answer set semantics. The main theorem shows how computing the answer sets for a program can be simplified when the program is split into parts. The programs covered by the theorem may use both negation as failure and classical negation, and their rules may have disjunctive heads. The usefulness of the concept of splitting for the investigation of answer sets is illustrated by several applications. First, we show that a conservative extension theorem by Gelfond and Przymusinska and a theorem on the closed world assumption by Gelfond and Lifschitz are easy consequences of the splitting theorem. Second, (...