Heterogeneous nonmonotonic multi-context systems (MCS) permit different logics to be used in different contexts, and link them via bridge rules. We investigate the role of symmetry detection and symmetry breaking in s...
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ISBN:
(纸本)9783642208942;9783642208959
Heterogeneous nonmonotonic multi-context systems (MCS) permit different logics to be used in different contexts, and link them via bridge rules. We investigate the role of symmetry detection and symmetry breaking in such systems to eliminate symmetric parts of the search space and, thereby, simplify the evaluation process. We propose a distributed algorithm that takes a local stance, i.e., computes independently the partial symmetries of a context and, in order to construct potential symmetries of the whole, combines them withthose partial symmetries returned by neighbouring contexts. We prove the correctness of our methods. We instantiate such symmetry detection and symmetry breaking in a multi-context system with contexts that use answer set programs, and demonstrate computational benefit on some recently proposed benchmarks.
Revision programming is a formalism to describe and enforce updates of belief sets and databases. that formalism was extended by Fitting who assigned annotations to revision atoms. Annotations provide a way to quantif...
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Revision programming is a formalism to describe and enforce updates of belief sets and databases. that formalism was extended by Fitting who assigned annotations to revision atoms. Annotations provide a way to quantify the confidence (probability) that a revision atom holds. the main goal of our paper is to reexamine the work of Fitting, argue that his semantics does not always provide results consistent with intuition, and to propose an alternative treatment of annotated revision programs. Our approach differs from that proposed by Fitting in two key aspects: we change the notion of a model of a program and we change the notion of a justified revision. We show that under this new approach fundamental properties of justified revisions of standard revision programs extend to the annotated case. (C) 2002 Elsevier Science B.V. All rights reserved.
We introduce a logic for knowledge representation and reasoning on protein-protein interactions. Modulo a theory, formulas describe protein structures and dynamic changes. they can be composed in order to add or remov...
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We introduce a logic for knowledge representation and reasoning on protein-protein interactions. Modulo a theory, formulas describe protein structures and dynamic changes. they can be composed in order to add or remove static and dynamic observations. A second-order circumscription operator then enables nonmonotonicreasoning on the changes implied by a formula. We introduce deduction rules that produce formulas which are, up to equivalence, in a first-order fragment with decidable satisfiability and validity. Importantly, the rules can produce circumscribed formulas.
To ensure a close relation between the answer sets of a program and those of its ground version, some answer set solvers deal with variables by requiring a safety condition on program rules. If we go beyond the syntax...
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ISBN:
(纸本)9783642042379
To ensure a close relation between the answer sets of a program and those of its ground version, some answer set solvers deal with variables by requiring a safety condition on program rules. If we go beyond the syntax of disjunctive programs, for instance by allowing rules with nested expressions, or perhaps even arbitrary first-order formulas, new definitions of safety are required. In this paper we consider a new concept of safety for formulas in quantified equilibrium logic where answer sets can be defined for arbitrary first-order formulas. the new concept captures and generalises two recently proposed safety definitions: that of Lee, Lifschitz and Palla (2008) as well as that of Bria, Faber and Leone (2008). We Study the main metalogical properties of safe formulas.
Prioritized logic programs (PLPs) have a mechanism of representing priority knowledge in logic programs. the declarative semantics of a PLP is given as preferred answer sets which are used for representing nonmonotoni...
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ISBN:
(数字)9783540398134
ISBN:
(纸本)3540201017
Prioritized logic programs (PLPs) have a mechanism of representing priority knowledge in logic programs. the declarative semantics of a PLP is given as preferred answer sets which are used for representing nonmonotonicreasoning as well as preference abduction. From the computational viewpoint, however, its implementation issues have little been studied and no sound procedure is known for computing preferred answer sets of PLPs. In this paper, we present a sound and complete procedure to compute all preferred answer sets of a PLP in answer set programming. the procedure is based on a program transformation from a PLP to a logic program and is realized on top of any procedure for answer set programming. the proposed technique also extends PLPs to handle dynamic preference and we address its application to legal reasoning.
In this paper we study the relation between the two main extensions of Answer Set programming with temporal modal operators: Temporal Equilibrium logic (TEL) and Temporal Answer Sets (TAS). On the one hand, TEL is a c...
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ISBN:
(纸本)9783642405648
In this paper we study the relation between the two main extensions of Answer Set programming with temporal modal operators: Temporal Equilibrium logic (TEL) and Temporal Answer Sets (TAS). On the one hand, TEL is a complete non-monotonic logicthat results from the combination of Linear-time Temporal logic (LTL) with Equilibrium logic. On the other hand, TAS is based on a richer modal approach, Dynamic LTL (DLTL), whereas its non-monotonic part relies on a reduct-based definition for a particular limited syntax. To integrate both approaches, we propose a Dynamic Linear-time extension of Equilibrium logic (DTEL) that allows accommodating both TEL and TAS as particular cases. With respect to TEL, DTEL incorporates more expressiveness thanks to the addition of dynamic logic operators, whereas with respect to TAS, DTEL provides a complete non-monotonic semantics applicable to arbitrary theories. In the paper, we identify cases in which both formalisms coincide and explain how this relation can be exploited for adapting existing TEL and TAS computation methods to the general case of DTEL.
In answer-set programming (ASP), many notions of program equivalence have been introduced and formally analysed. A particular line of research in this direction aims at studying conditions under which certain syntacti...
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ISBN:
(纸本)9783642042379
In answer-set programming (ASP), many notions of program equivalence have been introduced and formally analysed. A particular line of research in this direction aims at studying conditions under which certain syntactic constructs can be eliminated from programs preserving some given equivalence relation. In this paper, we continue this endeavour introducing novel conditions under which disjunction and negation can be eliminated from answer-set programs under relativised strong equivalence with projection. this notion is a generalisation of the usual strong-equivalence relation, as introduced by Lifschitz. Pearce, and Valverde, by allowing parametrisable context and Output alphabets, which is an important feature in view of practical programming techniques like the use of local variables and modules. We provide model-theoretic conditions that hold for a disjunctive logic program P precisely when there is a program Q, equivalent to P under our considered notion, Such that Q is either positive, normal, or Horn, respectively. Moreover, we outline how such a Q, called a casting of P, can be obtained, and consider complexity issues.
We investigate mca-programs, that is, logic programs with clauses built of monotone cardinality atoms of the form kX, where k is a non-negative integer and X is a finite set of propositional atoms. We develop a theory...
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We extend probabilistic action language pBC+ withthe notion of utility in decision theory. the semantics of the extended pBC+ can be defined as a shorthand notation for a decision-theoretic extension of the probabili...
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ISBN:
(纸本)9783030205287;9783030205270
We extend probabilistic action language pBC+ withthe notion of utility in decision theory. the semantics of the extended pBC+ can be defined as a shorthand notation for a decision-theoretic extension of the probabilistic answer set programming language LPMLN. Alternatively, the semantics of pBC+ can also be defined in terms of Markov Decision Process (MDP), which in turn allows for representing MDP in a succinct and elaboration tolerant way as well as leveraging an MDP solver to compute a pBC+ action description. the idea led to the design of the system PBCPLUS2MDP, which can find an optimal policy of a pBC+ action description using an MDP solver.
the paper provides a new approach for automated reasoning in a logic Program using extended Petri net models. the design includes extension of classical linear resolution of first order logic clauses by multi-resoluti...
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ISBN:
(纸本)0769530508
the paper provides a new approach for automated reasoning in a logic Program using extended Petri net models. the design includes extension of classical linear resolution of first order logic clauses by multi-resolution, where a set of clauses can be resolved concurrently without sacrificing any inference, thereby speeding-up the execution of the logic program. the speed-tip and utilization rate of resources are used as the performance evaluation metric to compare the performance of the proposed system withthe classical one.
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