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15
Agents that reason and negotiate by arguing
 Journal of Logic and Computation
, 1998
"... The need for negotiation in multiagent systems stems from the requirement for agents to solve the problems posed by their interdependence upon one another. Negotiation provides a solution to these problems by giving the agents the means to resolve their conflicting objectives, correct inconsistenci ..."
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Cited by 305 (59 self)
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The need for negotiation in multiagent systems stems from the requirement for agents to solve the problems posed by their interdependence upon one another. Negotiation provides a solution to these problems by giving the agents the means to resolve their conflicting objectives, correct inconsistencies in their knowledge of other agents ' world views, and coordinate a joint approach to domain tasks which benefits all the agents concerned. We propose a framework, based upon a system of argumentation, which permits agents to negotiate in order to establish acceptable ways of solving problems. The framework provides a formal model of argumentationbased reasoning and negotiation, details a design philosophy which ensures a clear link between the formal model and its practical instantiation, and describes a case study of this relationship for a particular class of architectures (namely those for beliefdesireintention agents).
Exploiting Data Dependencies in ManyValued Logics
 Journal of Applied NonClassical Logics
, 1996
"... . The purpose of this paper is to make some practically relevant results in automated theorem proving available to manyvalued logics with suitable modifications. We are working with a notion of manyvalued firstorder clauses which any finitelyvalued logic formula can be translated into and that h ..."
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Cited by 21 (7 self)
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. The purpose of this paper is to make some practically relevant results in automated theorem proving available to manyvalued logics with suitable modifications. We are working with a notion of manyvalued firstorder clauses which any finitelyvalued logic formula can be translated into and that has been used several times in the literature, but in an ad hoc way. We give a manyvalued version of polarity which in turn leads to natural manyvalued counterparts of Horn formulas, hyperresolution, and a DavisPutnam procedure. We show that the manyvalued generalizations share many of the desirable properties of the classical versions. Our results justify and generalize several earlier results on theorem proving in manyvalued logics. KEYWORDS: manyvalued logic, polarity, Horn formula, direct products of structures, resolution, DavisPutnam procedure Introduction The purpose of this paper is to make some practically relevant results in automated theorem proving available to manyvalue...
On Correct Program Schemas
"... We present our work on the representation and correctness of program schemas, in the context of logic program synthesis. Whereas most researchers represent schemas purely syntactically as higherorder expressions, we shall express a schema as an open firstorder theory that axiomatises a probl ..."
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Cited by 17 (11 self)
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We present our work on the representation and correctness of program schemas, in the context of logic program synthesis. Whereas most researchers represent schemas purely syntactically as higherorder expressions, we shall express a schema as an open firstorder theory that axiomatises a problem domain, called a specification framework, containing an open program that represents the template of the schema. We will show that using our approach we can define a meaningful notion of correctness for schemas, viz. that correct program schemas can be expressed as parametric specification frameworks containing templates that are steadfast, i.e. programs that are always correct provided their open relations are computed correctly.
Approximate Knowledge Compilation: The First Order Case
, 1996
"... Knowledge compilation procedures make a knowledge base more explicit so as make inference with respect to the compiled knowledge base tractable or at least more efficient. Most work to date in this area has been restricted to the propositional case, despite the importance of first order theories for ..."
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Cited by 17 (3 self)
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Knowledge compilation procedures make a knowledge base more explicit so as make inference with respect to the compiled knowledge base tractable or at least more efficient. Most work to date in this area has been restricted to the propositional case, despite the importance of first order theories for expressing knowledge concisely. Focusing on (LUB) approximate compilation (Selman and Kautz 1991), our contribution is twofold: ffl We present a new ground algorithm for approximate compilation which can produce exponential savings with respect to the previously known algorithm (Selman and Kautz 1991). ffl We show that both ground algorithms can be lifted to the first order case preserving their correctness for approximate compilation. Introduction Knowledge compilation procedures make a knowledge base (logical theory) \Sigma more explicit so as make inference with respect to the compiled knowledge base \Sigma ? tractable, or at least more efficient. The key idea is to invest time and ...
First order LUB approximations: characterization and algorithms
 Artif. Intell
, 2005
"... One of the major approaches to approximation of logical theories is the upper and lower bounds approach introduced in (Selman and Kautz, 1991, 1996). In this paper, we address the problem of lowest upper bound (LUB) approximation in a general setting. We characterize LUB approximations for arbitrary ..."
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Cited by 14 (0 self)
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One of the major approaches to approximation of logical theories is the upper and lower bounds approach introduced in (Selman and Kautz, 1991, 1996). In this paper, we address the problem of lowest upper bound (LUB) approximation in a general setting. We characterize LUB approximations for arbitrary target languages, both propositional and first order, and describe algorithms of varying generality and efficiency for all target languages, proving their correctness. We also examine some aspects of the computational complexity of the algorithms, both propositional and first order; show that they can be used to characterize properties of whole families of resolution procedures; discuss the quality of approximations; and relate LUB approximations to other approaches existing in the literature which are not typically seen in the approximation framework, and which go beyond the “knowledge compilation ” perspective that led to the introduction of LUBs.
Correctschemaguided Synthesis of Steadfast Programs
 In M. Lowry and Y. Ledru (eds), Proc. of ASE'97
, 1997
"... It can be argued that for (semi)automated software development, program schemas are indispensable, since they capture not only structured program design principles, but also domain knowledge, both of which are of crucial importance for hierarchical program synthesis. Most researchers represent sche ..."
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Cited by 11 (7 self)
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It can be argued that for (semi)automated software development, program schemas are indispensable, since they capture not only structured program design principles, but also domain knowledge, both of which are of crucial importance for hierarchical program synthesis. Most researchers represent schemas purely syntactically (as higherorder expressions) . This means that the knowledge captured by a schema is not formalised. We take a semantic approach and show that a schema can be formalised as an open (firstorder) logical theory that contains an open logic program. By using a special kind of correctness for open programs, called steadfastness, we can define and reason about the correctness of schemas. We also show how to use correct schemas to synthesise steadfast programs. 1. Introduction It can be argued that any systematic approach to software development must use some kind of schemabased strategies. In (semi)automated software development, program schemas become indispensable, s...
The Relationship between Logic Programs and Specifications  The Subset Example Revisited
, 1997
"... this paper, we argue that the relation between S and P ..."
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Cited by 11 (5 self)
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this paper, we argue that the relation between S and P
Forms of Logic Specifications: A Preliminary Study
 Proc. LOPSTR'96, pages 295312, LNCS 1207
, 1997
"... . There is no universal agreement on exactly what form a specification should take, what part it should play in synthesis, and what its precise relationship with the specified program should be. In logic programming, the role of specification is all the more unclear since logic programs are often us ..."
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Cited by 6 (4 self)
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. There is no universal agreement on exactly what form a specification should take, what part it should play in synthesis, and what its precise relationship with the specified program should be. In logic programming, the role of specification is all the more unclear since logic programs are often used as executable specifications. In this paper we take the view that specifications should be set in the context of the problem domain, which we call a framework . We conduct a preliminary study of two useful forms of logic specifications: ifandonlyif and partial specifications. First we set up a threetier formalism for synthesis, the toptier being a framework. Then within this formalism we define these two forms of specifications, and discuss their roles in synthesis. 1 Introduction The purpose of program synthesis is to derive programs that are correct wrt to their (formal or informal) specifications. There is no universal agreement, however, on exactly what form a specification sho...
Isoinitial Models for Logic Programs: A Preliminary Study
 Proceedings of the 1998 Joint Conference on Declarative Programming
, 1998
"... The Herbrand model H of a definite logic program P is an initial model among the class of all the models of P , interpreting P as an initial theory. Such a theory proves (computes) only positive literals (atoms) in P , so it does not deal with negation. In this paper, we introduce isoinitial models ..."
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Cited by 4 (4 self)
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The Herbrand model H of a definite logic program P is an initial model among the class of all the models of P , interpreting P as an initial theory. Such a theory proves (computes) only positive literals (atoms) in P , so it does not deal with negation. In this paper, we introduce isoinitial models of logic programs. We show that isoinitial semantics deals with negation, and works in a uniform way for definite and normal logic programs. Moreover, the lack of an isoinitial model signals the absence of information. Thus it also provides a unifying semantics for closed and open logic programs. Keywords: Semantics, isoinitial models, negation 1 Introduction The intended model of a standard (Horn clause) logic program P is its Herbrand model H. It interprets P under the Closed World Assumption [11]. Considering the class of all the models of P , H interprets P as an initial (Horn) theory [5]. A distinguishing feature of an initial theory P is that, in general, it proves (computes) only p...