A Theory of Forgetting in Logic Programming
نویسندگان
چکیده
The study of forgetting for reasoning has attracted considerable attention in AI. However, much of the work on forgetting, and other related approaches such as independence, irrelevance and novelty, has been restricted to the classical logics. This paper describes a detailed theoretical investigation of the notion of forgetting in the context of logic programming. We first provide a semantic definition of forgetting under the answer sets for extended logic programs. We then discuss the desirable properties and some motivating examples. An important result of this study is an algorithm for computing the result of forgetting in a logic program. Furthermore, we present a modified version of the algorithm and show that the time complexity of the new algorithm is polynomial with respect to the size of the given logic program if the size of certain rules is fixed. We show how the proposed theory of forgetting can be used to characterize the logic program updates.
منابع مشابه
Forgetting and Conflict Resolving in Disjunctive Logic Programming
We establish a declarative theory of forgetting for disjunctive logic programs. The suitability of this theory is justified by a number of desirable properties. In particular, one of our results shows that our notion of forgetting is completely captured by the classical forgetting. A transformation-based algorithm is also developed for computing the result of forgetting. We also provide an anal...
متن کاملSemantic forgetting in answer set programming
The notion of forgetting, also known as variable elimination, has been investigated extensively in the context of classical logic, but less so in (nonmonotonic) logic programming and nonmonotonic reasoning. The few approaches that exist are based on syntactic modifications of a program at hand. In this paper, we establish a declarative theory of forgetting for disjunctive logic programs under a...
متن کاملKnowledge Forgetting in Circumscription: A Preliminary Report
The theory of (variable) forgetting has received significant attention in nonmonotonic reasoning, especially, in answer set programming. However, the problem of establishing a theory of forgetting for some expressive nonmonotonic logics such as McCarthy’s circumscription is rarely explored. In this paper a theory of forgetting for propositional circumscription is proposed, which is not a straig...
متن کاملForgetting in Logic Programs under Strong Equivalence
In this paper, we propose a semantic forgetting for arbitrary logic programs (or propositional theories) under answer set semantics, called HT-forgetting. The HTforgetting preserves strong equivalence in the sense that strongly equivalent logic programs will remain strongly equivalent after forgetting the same set of atoms. The result of an HT-forgetting is always expressible by a logic program...
متن کاملTowards a Knowledge Level Analysis of Forgetting
Forgetting has been addressed in various areas in KR, including classical logic, logic programming, modal logic, and description logics. Here, we view forgetting as an abstract operator, independent of the underlying logic. We argue that forgetting amounts to a reduction in the signature of a language of a logic, and that the result of forgetting elements of a signature in a theory is the set o...
متن کامل