Results 1  10
of
27
Relating Defeasible and Normal Logic Programming through Transformation Properties
, 2001
"... This paper relates the Defeasible Logic Programming (DeLP ) framework and its semantics SEM DeLP to classical logic programming frameworks. In DeLP we distinguish between two different sorts of rules: strict and defeasible rules. Negative literals (A) in these rules are considered to represent cl ..."
Abstract

Cited by 75 (28 self)
 Add to MetaCart
This paper relates the Defeasible Logic Programming (DeLP ) framework and its semantics SEM DeLP to classical logic programming frameworks. In DeLP we distinguish between two different sorts of rules: strict and defeasible rules. Negative literals (A) in these rules are considered to represent classical negation. In contrast to this, in normal logic programming (NLP ), there is only one kind of rules, but the meaning of negative literals (notA) is different: they represent a kind of negation as failure, and thereby introduce defeasibility. Various semantics have been defined for NLP, notably the wellfounded semantics WFS and the stable semantics Stable. In this paper we consider the transformation properties for NLP introduced by Brass and Dix and suitably adjusted for the DeLP framework. We show which transformation properties are satisfied, thereby identifying aspects in which NLP and DeLP differ. We contend that the transformation rules presented in this paper can he...
TransformationBased BottomUp Computation of the WellFounded Model
, 1997
"... . We present a bottomup algorithm for the computation of the wellfounded model of nondisjunctive logic programs. Our method is based on the elementary program transformations studied by Brass and Dix [6, 7]. However, their "residual program" can grow to exponential size, whereas for functionfre ..."
Abstract

Cited by 38 (4 self)
 Add to MetaCart
. We present a bottomup algorithm for the computation of the wellfounded model of nondisjunctive logic programs. Our method is based on the elementary program transformations studied by Brass and Dix [6, 7]. However, their "residual program" can grow to exponential size, whereas for functionfree programs our "program remainder " is always polynomial in the size, i.e. the number of tuples, of the extensional database (EDB). As in the SLGresolution of Chen and Warren [11, 12, 13], we do not only delay negative but also positive literals if they depend on delayed negative literals. When disregarding goaldirectedness, which needs additional concepts, our approach can be seen as a simplified bottomup version of SLGresolution applicable to rangerestricted Datalog programs. Since our approach is also closely related to the alternating fixpoint procedure [27, 28], it can possibly serve as a basis for an integration of the resolutionbased, fixpointbased, and transformationbased ev...
Knowledge Representation with Logic Programs
 DEPT. OF CS OF THE UNIVERSITY OF KOBLENZLANDAU
, 1996
"... In this tutorialoverview, which resulted from a lecture course given by the authors at ..."
Abstract

Cited by 31 (6 self)
 Add to MetaCart
In this tutorialoverview, which resulted from a lecture course given by the authors at
Heterogeneous Active Agents, III: Polynomially Implementable Agents
 Artificial Intelligence
, 2000
"... In [17], two of the authors have introduced techniques to build agents on top of arbitrary data structures, and to "agentize" new/existing programs. They provided a series of successively more sophisticated semantics for such agent systems, and showed that as these semantics become epistemically ..."
Abstract

Cited by 25 (8 self)
 Add to MetaCart
In [17], two of the authors have introduced techniques to build agents on top of arbitrary data structures, and to "agentize" new/existing programs. They provided a series of successively more sophisticated semantics for such agent systems, and showed that as these semantics become epistemically more desirable, a computational price may need to be paid. In this paper, we identify a class of agents that are called weakly regularthis is done by first identifying a fragment of agent programs [17] called weakly regular agent programs (WRAPs for short).
Super Logic Programs
, 1996
"... Recently, considerable interest and research e#ort has been given to the problem of finding a suitable extension of the logic programming paradigm beyond the class of normal logic programs. In order to demonstrate that a class of programs can be justifiably called an extension of logic programs one ..."
Abstract

Cited by 21 (2 self)
 Add to MetaCart
Recently, considerable interest and research e#ort has been given to the problem of finding a suitable extension of the logic programming paradigm beyond the class of normal logic programs. In order to demonstrate that a class of programs can be justifiably called an extension of logic programs one should be able to argue that: . the proposed syntax of such programs resembles the syntax of logic programs but it applies to a significantly broader class of programs; . the proposed semantics of such programs constitutes an intuitively natural extension of the semantics of normal logic programs; . there exists a reasonably simple procedural mechanism allowing, at least in principle, to compute the semantics; . the proposed class of programs and their semantics is a special case of a more general nonmonotonic formalism which clearly links it to other wellestablished nonmonotonic formalisms. In this paper we propose a specific class of extended logic programs which will be (modestly) called super logic programs or just superprograms. We will argue that the class of superprograms satisfies all of the above conditions, and, in addition, is su#ciently flexible to allow various applicationdependent extensions and modifications. We also provide a brief description of a Prolog implementation of a queryanswering interpreter for the class of superprograms which is available via FTP and WWW. Keywords: NonMonotonic Reasoning, Logics of Knowledge and Beliefs, Semantics of Logic Programs and Deductive Databases. # An extended abstract of this paper appeared in the Proceedings of the Fifth International Conference on Principles of Knowledge Representation and Reasoning (KR'96), Boston, Massachusetts, 1996, pp. 529541. + Partially supported by the National Science Fou...
DisLoP: A Research Project on Disjunctive Logic Programming
 AI COMMUNICATIONS
, 1997
"... This paper gives a brief highlevel description of what has been done in the Disjunctive Logic Programmingproject (funded by Deutsche ForschungsGemeinschaft), undertaken by the University of Koblenz since July 1995. We present the main ideas, cite the relevant papers and point to the implemented s ..."
Abstract

Cited by 19 (4 self)
 Add to MetaCart
This paper gives a brief highlevel description of what has been done in the Disjunctive Logic Programmingproject (funded by Deutsche ForschungsGemeinschaft), undertaken by the University of Koblenz since July 1995. We present the main ideas, cite the relevant papers and point to the implemented systems and how to access them. This paper also serves as a brief survey of the current status of disjunctive logic programming by highlighting important developments and providing enough pointers for further reading.
Disjunctive Logic Programming: A Survey And Assessment
, 2002
"... We describe the elds of disjunctive logic programming and disjunctive deductive databases from the time of their inception to the current time. Contributions with respect to semantics, implementations and applications are surveyed. ..."
Abstract

Cited by 16 (0 self)
 Add to MetaCart
We describe the elds of disjunctive logic programming and disjunctive deductive databases from the time of their inception to the current time. Contributions with respect to semantics, implementations and applications are surveyed.
Comparisons and computation of wellfounded semantics for disjunctive logic programs
 ACM Transactions on Computational Logic
, 2005
"... Much work has been done on extending the wellfounded semantics to general disjunctive logic programs and various approaches have been proposed. However, these semantics are different from each other and no consensus is reached about which semantics is the most intended. In this paper we look at dis ..."
Abstract

Cited by 14 (3 self)
 Add to MetaCart
Much work has been done on extending the wellfounded semantics to general disjunctive logic programs and various approaches have been proposed. However, these semantics are different from each other and no consensus is reached about which semantics is the most intended. In this paper we look at disjunctive wellfounded reasoning from different angles. We show that there is an intuitive form of the wellfounded reasoning in disjunctive logic programming which can be characterized by slightly modifying some existing approaches to defining disjunctive wellfounded semantics, including program transformations, argumentation, unfounded sets (and resolutionlike procedure). By employing the techniques developed by Brass and Dix in their transformationbased approach, we also provide a bottomup procedure for this semantics. The significance of our work is not only in clarifying the relationship among different approaches, but also shed some light on what is an intended wellfounded semantics for disjunctive logic programs. Categories and Subject Descriptors: F.4.1 [Mathematical Logic and Formal Languages]: Mathematical Logic—logic and constraint programming; computational logic; I.2.3 [Artificial Intelligence]: Deduction and Theorem Proving—logic programming; nonmonotonic reasoning
ArgumentationBased Abduction in Disjunctive Logic Programming
 Journal of Logic programming
, 2000
"... In this paper we propose an argumentationbased semantic framework, called DAS, for disjunctive logic programming. The basic idea is to translate a disjunctive logic program into an argumentationtheoretic framework. One unique feature of our proposed framework is to consider the disjunctions of ..."
Abstract

Cited by 11 (4 self)
 Add to MetaCart
In this paper we propose an argumentationbased semantic framework, called DAS, for disjunctive logic programming. The basic idea is to translate a disjunctive logic program into an argumentationtheoretic framework. One unique feature of our proposed framework is to consider the disjunctions of negative literals as possible assumptions so as to represent incomplete information. In our framework, three semantics PDH, CDH and WFDH are defined by three kinds of acceptable hypotheses to represent credulous, moderate and skeptical reasoning in AI, respectively. Further more, our semantic framework can be extended to a wider class than that of disjunctive programs (called bidisjunctive logic programs). In addition to being a first serious attempt of establishing an argumentationtheoretic framework for disjunctive logic programming, DAS integrates and naturally extends many key semantics, such as the minimal models, EGCWA, the wellfounded model, and the disjunctive stable models. In particular, novel and interesting argumentationtheoretic characterizations of the EGCWA and the disjunctive stable semantics are shown. Thus the framework presented in this paper does not only provide a new way of performing argumentation (abduction) in disjunctive deductive databases, but also is a simple, intuitive and unifying semantic framework for disjunctive logic programming.