Results 1  10
of
39
The DLV System for Knowledge Representation and Reasoning
 ACM Transactions on Computational Logic
, 2002
"... Disjunctive Logic Programming (DLP) is an advanced formalism for knowledge representation and reasoning, which is very expressive in a precise mathematical sense: it allows to express every property of finite structures that is decidable in the complexity class ΣP 2 (NPNP). Thus, under widely believ ..."
Abstract

Cited by 320 (78 self)
 Add to MetaCart
Disjunctive Logic Programming (DLP) is an advanced formalism for knowledge representation and reasoning, which is very expressive in a precise mathematical sense: it allows to express every property of finite structures that is decidable in the complexity class ΣP 2 (NPNP). Thus, under widely believed assumptions, DLP is strictly more expressive than normal (disjunctionfree) logic programming, whose expressiveness is limited to properties decidable in NP. Importantly, apart from enlarging the class of applications which can be encoded in the language, disjunction often allows for representing problems of lower complexity in a simpler and more natural fashion. This paper presents the DLV system, which is widely considered the stateoftheart implementation of disjunctive logic programming, and addresses several aspects. As for problem solving, we provide a formal definition of its kernel language, functionfree disjunctive logic programs (also known as disjunctive datalog), extended by weak constraints, which are a powerful tool to express optimization problems. We then illustrate the usage of DLV as a tool for knowledge representation and reasoning, describing a new declarative programming methodology which allows one to encode complex problems (up to ∆P 3complete problems) in a declarative fashion. On the foundational side, we provide a detailed analysis of the computational complexity of the language of
Logic Programming and Knowledge Representation  the AProlog perspective
 Artificial Intelligence
, 2002
"... In this paper we give a short introduction to logic programming approach to knowledge representation and reasoning. The intention is to help the reader to develop a 'feel' for the field's history and some of its recent developments. The discussion is mainly limited to logic programs under the answer ..."
Abstract

Cited by 87 (0 self)
 Add to MetaCart
In this paper we give a short introduction to logic programming approach to knowledge representation and reasoning. The intention is to help the reader to develop a 'feel' for the field's history and some of its recent developments. The discussion is mainly limited to logic programs under the answer set semantics. For understanding of approaches to logic programming build on wellfounded semantics, general theories of argumentation, abductive reasoning, etc., the reader is referred to other publications.
Characterizations of the Disjunctive Wellfounded Semantics: Confluent Calculi and Iterated GCWA
 Journal of Automated Reasoning
, 1997
"... . Recently Brass and Dix have introduced the semantics DWFS for general disjunctive logic programs. The interesting feature of this approach is that it is both semantically and prooftheoretically founded. Any program \Phi is associated a normalform res(\Phi), called the residual program, by a non ..."
Abstract

Cited by 32 (10 self)
 Add to MetaCart
. Recently Brass and Dix have introduced the semantics DWFS for general disjunctive logic programs. The interesting feature of this approach is that it is both semantically and prooftheoretically founded. Any program \Phi is associated a normalform res(\Phi), called the residual program, by a nontrivial bottomup construction using least fixpoints of two monotonic operators. We show in this paper, that the original calculus, consisting of some simple transformations, has a very strong and appealing property: it is confluent and terminating. This means that all the transformations can be applied in any order: we always arrive at an irreducible program (no more transformation is applicable) and this program is already uniquely determined. Moreover, it coincides with the normalform res(\Phi) of the program we started with. The semantics DWFS can be read off from res(\Phi) immediately. No proper subset of the calculus has these properties  only when we restrict to certain subclasse...
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
Prolegomena to Logic Programming for NonMonotonic Reasoning
"... The present prolegomena consist, as all indeed do, in a critical discussion serving to introduce and interpret the extended works that follow in this book. As a result, the book is not a mere collection of excellent papers in their own specialty, but provides also the basics of the motivation, b ..."
Abstract

Cited by 22 (16 self)
 Add to MetaCart
The present prolegomena consist, as all indeed do, in a critical discussion serving to introduce and interpret the extended works that follow in this book. As a result, the book is not a mere collection of excellent papers in their own specialty, but provides also the basics of the motivation, background history, important themes, bridges to other areas, and a common technical platform of the principal formalisms and approaches, augmented with examples. In the
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...
On Active Deductive Databases: The Statelog Approach
 IN TRANSACTIONS AND CHANGE IN LOGIC DATABASES
, 1998
"... After brie y reviewing the basic notions and terminology of active rules and relating them to production rules and deductive rules, respectively, we survey a number of formal approaches to active rules. Subsequently, we present our own stateoriented logical approach to active rules which combines ..."
Abstract

Cited by 20 (2 self)
 Add to MetaCart
After brie y reviewing the basic notions and terminology of active rules and relating them to production rules and deductive rules, respectively, we survey a number of formal approaches to active rules. Subsequently, we present our own stateoriented logical approach to active rules which combines the declarative semantics of deductive rules with the possibility to de ne updates in the style of production rules and active rules. The resulting language Statelog is surprisingly simple, yet captures many features of active rules including composite event detection and di erent coupling modes. Thus, it can be used for the formal analysis of rule properties like termination and expressive power. Finally, we showhow nested transactions can be modeled in Statelog, both from the operational and the modeltheoretic perspective.
A Fixpoint Semantics and an SLDResolution Calculus for Modal Logic Programs
, 2001
"... We propose a modal logic programming language called MProlog, which is as expressive as the general modal Horn fragment. We give a fixpoint semantics and an SLDresolution calculus for MProlog in all of the basic serial modal logics KD, T, KDB, B, KD4, S4, KD5, KD45, and S5. For an MProlog program P ..."
Abstract

Cited by 15 (13 self)
 Add to MetaCart
We propose a modal logic programming language called MProlog, which is as expressive as the general modal Horn fragment. We give a fixpoint semantics and an SLDresolution calculus for MProlog in all of the basic serial modal logics KD, T, KDB, B, KD4, S4, KD5, KD45, and S5. For an MProlog program P and for L being one of the mentioned logics, we define an operator TL,P, which has the least fixpoint IL,P. This fixpoint is a set of formulae, which may contain labeled forms of the modal operator ✸, and is called the least Lmodel generator of P. The standard model of IL,P is shown to be a least Lmodel of P. The SLDresolution calculus for MProlog is designed with a similar style as for classical logic programming. It is sound and complete. We also extend the calculus for MProlog in the almost serial modal logics KB, K 5, K 45, and KB5. 1
Linearly Bounded Reformulations of Conjunctive Databases (Extended Abstract)
 In Proc. of DOOD
, 2000
"... Database reformulation is the process of rewriting the data and rules of a deductive database in a functionally equivalent manner. ..."
Abstract

Cited by 13 (5 self)
 Add to MetaCart
Database reformulation is the process of rewriting the data and rules of a deductive database in a functionally equivalent manner.