About the Book
ThesearetheproceedingsoftheSixthInternationalConferenceonLogicP- grammingandNonmonotonicReasoning (LPNMR2001). The conference was heldinViennafrom17thto19thofSeptember,2001. Itwascollocatedwiththe JointGerman/AustrianConferenceonArti?cialIntelligence(24thGerman/9th AustrianConferenceonArti?cialIntelligence),KI2001. LPNMR conferences aim to promote research in logic-based programming languages, database systems, nonmonotonic reasoning, and knowledge rep- sentation. LPNMR2001 was the sixth conference in the series. The previous meetingswereheldinWashington,DC,in1991,inLisbon,Portugal,in1993,in Lexington,Kentucky,in1995,inDagstuhl,Germany,in1997,andinElPaso, Texas,in1999. ThetechnicalprogramofLPNMR2001wascomprisedof?veinvitedtalks thatweregivenbyJur .. genDix,GeorgGottlob,PhokionKolaitis,MaurizioLe- erini,andChiakiSakama. Italsocontained23technicalpresentationsselected bytheprogramcommitteeduringarigorousreviewprocess. Finally,asapart ofthetechnicalprogram,theconferencefeaturedaspecialsessioncomprisedof ninepresentationsanddemonstrationsofimplementednonmonotonicreasoning systems. Allthesecontributionsareincludedintheproceedings.
Many individuals workedfor the success of the conference. Special thanks areduetoallmembersoftheprogramcommitteeandtoadditionalreviewers fortheire?ortstoproducefairandthoroughevaluationsofsubmittedpapers. Furthermore, we would like to thank the members of the Knowledge Based SystemsGroupoftheViennaUniversityofTechnology,whichtookcareofthe localorganization. Weparticularlyappreciatedthenevertiringe?ortofElfriede Nedoma,secretarytothegroup. WewouldalsoliketothankGerdBrewkafor hissupportiveroleinarrangingthecollocationoftheconferencewithKI2001. Last,butnotleast,wethankthesponsoringinstitutionsfortheirgenerosity.
September2001 ThomasEiter WolfgangFaber Miros lawTruszczynski ' Conference Organization ProgramCo-chairs ThomasEiter(ViennaUniversityofTechnology,Austria) Miros lawTruszczynski ' (UniversityofKentucky,USA) ProgramCommittee AlexanderBochman(HolonAcademicInstituteofTechnology,Israel) PieroBonatti(Universit' adegliStudiMilano/Crema,Italy) GerhardBrewka(UniversityofLeipzig,Germany) JamesDelgrande(SimonFraserUniversity,Canada) MarcDenecker(KatholiekeUniversiteitLeuven,Belgium) NormanFoo(UniversityofNewSouthWales,Australia) MichaelGelfond(TexasTechUniversity,USA) KatsumiInoue(KobeUniversity,Japan) AntonisKakas(UniversityofCyprus) NicolaLeone(Universit' adegliStudidellaCalabria,Italy) VladimirLifschitz(UniversityofTexasatAustin,USA) FangzhenLin(TheHongKongUniversityofScienceandTechnology,China) VictorMarek(UniversityofKentuckyatLexington,USA) ZhangMing-Yi(GuizhouAcademyofSciences,China) IlkkaNiemel. a(HelsinkiUniversityofTechnology,Finland) Lu'?sMonizPereira(UniversidadeNovadeLisboa,Portugal) MarcoSchaerf(Universitad ' iRoma"LaSapienza,"Italy) TorstenSchaub(UniversityofPotsdam,Germany) FrancescaToni(ImperialCollege,London,U. K.
) Li-YanYuan(UniversityofAlberta,Canada) Publicity Chair WolfgangFaber(ViennaUniversityofTechnology,Austria) Organization VII Additional Reviewers Jos'eAlferes MehmetOrgun CristinaBaroglio MauricePagnucco KrysiaBroda VivianaPatti MauriceBruynooghe NikolayPelov FrancescoBuccafurri GeraldPfeifer CarlosDam'asio FabrizioRiguzzi EmmanuelDeMot RiccardoRosati YannisDimopoulos GiulianaSabbatini EsraErdem FaribaSadri WolfgangFaber ChiakiSakama DayaGaur FrancescoScarcello JensHappe TommiSyrjanen TomiJanhunen AndreaTettamanzi JoohyungLee BertVanNu?elen NicolaLeone HelmutVeith ThomasLinke GerardVreeswijk ThomasLukasiewicz KewenWang PaoloMancarella Jia-HuaiYou CristinelMateis DongmoZhang RobMiller Sponsoring Institutions We would like to acknowledge ?nancial support for the conference from the EuropeanO?ceofAerospaceResearchandDevelopment(EOARD),underc- tractF61775-01-WF077,theAustrianComputerSociety(OCG),theEuropean Commission,theAustrianMinistryofTransport,Innovation&Technology,and Microsoft. Table of Contents Invited Papers AComputationalLogicApproachtoHeterogenousAgentSystems ...1 JurgenDix DeclarativeInformationExtraction,WebCrawling, andRecursiveWrappingwithLixto ...2
1 RobertBaumgartner,SergioFlesca,andGeorgGottlob OntheComplexityofModelCheckingandInference inMinimalModels(ExtendedAbstract) ...42 LefterisM. KirousisandPhokionG. Kolaitis DataIntegrationNeedsReasoning ...54 MaurizioLenzerini NonmonotonicInductiveLogicProgramming ...62 ChiakiSakama Regular Papers StrongEquivalenceforLogicPrograms andDefaultTheories(MadeEasy)...81 HudsonTurner OntheE?ectofDefaultNegationontheExpressiveness ofDisjunctiveRules ...93 TomiJanhunen OntheExpressibilityofStableLogicProgramming ...107 V. W. MarekandJ. B. Remmel OntheRelationshipbetweenDefeasibleLogic andWell-FoundedSemantics ...121 GerhardBrewka AComparativeStudyofWell-FoundedSemantics forDisjunctiveLogicPrograms ...133 KewenWang ReasoningwithOpenLogicPrograms ...147 PieroA. Bonatti RepresentationofIncompleteKnowledgebyInduction ofDefaultTheories...
Table of Contents:
Invited Papers.- A Computational Logic Approach to Heterogenous Agent Systems.- Declarative Information Extraction, Web Crawling, and Recursive Wrapping with Lixto.- On The Complexity of Model Checking and Inference in Minimal Models.- Data Integration Needs Reasoning.- Nonmonotomic Inductive Logic Programming.- Regular Papers.- Strong Equivalence for Logic Programs and Default Theories (Made Easy).- On the Effect of Default Negation on the Expressiveness of Disjunctive Rules.- On the Expressibility of Stable Logic Programming.- On the Relationship between Defeasible Logic and Well-Founded Semantics.- A Comparative Study of Well-Founded Semantics for Disjunctive Logic Programs.- Reasoning with Open Logic Programs.- Representation of Incomplete Knowledge by Induction of Default Theories.- Explicity Using Default Knowledge in Concept Learning: An Extended Description Logics Plus Strict and Default Rules.- Declarative Specification and Solution of Combinatorial Auctions Using Logic Programming.- Bounded LTL Model Checking with Stable Models.- Diagnosing Physical Systems in A-Prolog.- Planning with Different Forms of Domain-Dependent Control Knowledge — An Answer Set Programming Approach.- Encoding Solutions of the Frame Problem in Dynamic Logic.- ?-RES: Reasoning about Actions, Events and Observations.- Omega-Restricted Logic Programs.- Improving ASP Instantiators by Join-Ordering Methods.- Optimizing the Computation of Heuristics for Answer Set Programming Systems.- New Generation Systems for Non-monotonic Reasoning.- Algorithms for Computing X-Minimal Models.- Fixpoint Characterizations for Many-Valued Disjunctive Logic Programs with Probabilistic Semantics.- Multi-adjoint Logic Programming with Continous Semantics.- Multi-dimensional Dynamic KnowledgeRepresentation.- Antitonic Logic Programs.- System Description.- A-system: Declarative Programming with Abduction.- An Update Front-End for Extended Logic Programs.- aspps — An Implementation of Answer-Set Programming with Propositional Schemata.- NoMoRe: A System for Non-Monotonic Reasoning under Answer Set Semantics.- plp: A Generic Compiler for Ordered Logic Programs.- Prototypes for Reasoning with Infinite Stable Models and Function Symbols.- psmodels: Stable Models Based on Pertinence.- System Description: DLV.- System Description: The DLVK Planning System.- The Smodels System.- The USA-Advisor: A Case Study in Answer Set Planning.
