We prove two properties of logic programs under the answer set semantics that may be useful in connection with applications of logicprogramming to representing causality and to planning. One theorem is about the use ...
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(纸本)3540667490
We prove two properties of logic programs under the answer set semantics that may be useful in connection with applications of logicprogramming to representing causality and to planning. One theorem is about the use of disjunctive rules to express that an atom is exogenous. the other provides an alternative way of expressing that a plan does not include concurrently executed actions.
Recently there has been increased interest in logicprogramming-based default reasoning approaches which are not using negation-as-failure in their object language. Instead, default reasoning is modelled by rules and ...
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(纸本)3540667490
Recently there has been increased interest in logicprogramming-based default reasoning approaches which are not using negation-as-failure in their object language. Instead, default reasoning is modelled by rules and a priority relation among them. Historically the first logic in this class was Defeasible logic. In this paper we will study its relationship to other approaches which also rely on the idea of using logic rules and priorities. In particular we will study sceptical LPwNF, courteous logic programs, and priority logic.
this paper continues the line of research on representing actions, on the automation of commonsense reasoning and on planning that deals with causal theories and with action language C. We show here that many of the i...
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(纸本)3540667490
this paper continues the line of research on representing actions, on the automation of commonsense reasoning and on planning that deals with causal theories and with action language C. We show here that many of the ideas developed in that work can be formulated in terms of logic programs under the answer set semantics, without mentioning causal theories. the translations from C into logicprogrammingthat we investigate serve as a basis for the use of systems for computing answer sets to reason about action domains described in C and to generate plans in such domains.
this paper introduces techniques for updating knowledge bases represented in extended logic programs. three different types of updates, view updates, theory updates, and inconsistency removal, are considered. We formu...
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(纸本)3540667490
this paper introduces techniques for updating knowledge bases represented in extended logic programs. three different types of updates, view updates, theory updates, and inconsistency removal, are considered. We formulate these updates through abduction, and provide methods for computing them with update programs. An update program is an extended logic program which specifies changes on abductive hypotheses, then updates are computed by the U-minimal answer sets of an update program. the proposed technique provides a uniform framework for these different types of updates, and each update is computed using existing procedures of logicprogramming.
We investigate the problem of reasoning in nonmonotonic extensions of first-order logic. In particular, we study reasoning in first-order MKNF, the modal logic of minimal knowledge and negation as failure introduced b...
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(纸本)3540667490
We investigate the problem of reasoning in nonmonotonic extensions of first-order logic. In particular, we study reasoning in first-order MKNF, the modal logic of minimal knowledge and negation as failure introduced by Lifschitz. MKNF can be considered as a unifying framework for several nonmonotonic formalisms, including default logic, autoepistemic logic, circumscription, and logicprogramming. By suitably extending deduction methods for propositional nonmonotonic logics, we define techniques for reasoning in significant subsets of first-order MKNF, which allow for characterizing decidable fragments of first-order nonmonotonic modal logics. Due to the expressive abilities of MKNF, such techniques can be seen as general reasoning methods for several nonmonotonic formalisms based on first-order logic. We also analyze the relationship between such decidable fragments of MKNF and disjunctive Datalog.
In general, the set of stable models of a recursive propositional logic program can be quite complex. For example, it follows from results of Marek, Nerode, and Remmel [8] that there exists finite predicate logic prog...
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ISBN:
(纸本)3540667490
In general, the set of stable models of a recursive propositional logic program can be quite complex. For example, it follows from results of Marek, Nerode, and Remmel [8] that there exists finite predicate logic programs and recursive propositional logic programs which have stable models but no hyperarithmetic stable models. In this paper, we shall define several conditions which ensure that recursive logic program has astable model which is recursive.
dlv is a knowledge representation system, based on disjunctive logicprogramming, which offers front-ends to several advanced KR formalisms. this paper describes new techniques for the computation of answer sets of di...
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ISBN:
(纸本)3540667490
dlv is a knowledge representation system, based on disjunctive logicprogramming, which offers front-ends to several advanced KR formalisms. this paper describes new techniques for the computation of answer sets of disjunctive logic programs, that have been developed and implemented in the dlv system. these techniques try to "push" the query goals in the process of model generation (query goals are often present either explicitly, like in planning and diagnosis, or implicitly in the form of integrity constraints). this way, a lot of useless models are discarded "a priori" and the computation converges rapidly toward the generation of the "right" answer set. A few preliminary benchmarks show dramatic efficiency gains due to the new techniques.
We show how a class of domains written in the Language E, a high level language for reasoning about actions, narratives and. change, can be translated into the argumentation framework of logicprogramming without Nega...
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(纸本)3540667490
We show how a class of domains written in the Language E, a high level language for reasoning about actions, narratives and. change, can be translated into the argumentation framework of logicprogramming without Negation as Failure (LPwNF). this translation enables us 1) to understand default persistence as captured by various temporal reasoning frameworks in a simple and natural way, by assigning higher priority to information about effects of later actions over effects of earlier actions;2) to develop an argumentation-based computational model for this type of reasoning in logicprogramming goal-driven style.
We present many-valued disjunctive logic programs in which classical disjunctive logic program clauses are extended by a truth value that respects the material implication. Interestingly, these many-valued disjunctive...
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(纸本)3540667490
We present many-valued disjunctive logic programs in which classical disjunctive logic program clauses are extended by a truth value that respects the material implication. Interestingly, these many-valued disjunctive logic programs have both a probabilistic semantics in probabilities over possible worlds and a truth-functional semantics. We then define minimal, perfect, and stable models and show that they have the same properties like their classical counterparts. In particular, perfect and stable models are always minimal models. Under local stratification, the perfect model semantics coincides withthe stable model semantics. Finally, we show that some special cases of propositional many-valued disjunctive logicprogramming under minimal, perfect, and stable model semantics have the same complexity like their classical counterparts.
this paper reports on systematic research which aims to classify non-monotonic logics by their expressive power. the classification is based on translation functions that satisfy three important criteria: polynomialit...
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ISBN:
(纸本)3540667490
this paper reports on systematic research which aims to classify non-monotonic logics by their expressive power. the classification is based on translation functions that satisfy three important criteria: polynomiality, faithfulness and modularity (PFM for short). the basic method for classification is to prove that PFM translation functions exist (or do not exist) between certain logics. As a result, non-monotonic logics can be arranged to form a hierarchy. this paper gives an overview of the current expressive power hierarchy (EPH) and investigates semi-normal default logic as well as prerequisite-free and semi-normal default logic in order to locate their exact positions in the hierarchy.
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