Table Of ContentMarkov Logic:
An Interface Layer for
Artificial Intelligence
Synthesis Lectures on
Artificial Intelligence and
Machine Learning
Editors
RonaldJ.Brachman,Yahoo!Research
ThomasDietterich,OregonStateUniversity
MarkovLogic:AnInterfaceLayerforArtificialIntelligence
PedroDomingosandDanielLowd
2009
IntroductiontoSemi-SupervisedLearning
XiaojinZhuandAndrewB.Goldberg
2009
ActionProgrammingLanguages
MichaelThielscher
2008
RepresentationDiscoveryusingHarmonicAnalysis
SridharMahadevan
2008
EssentialsofGameTheory:AConciseMultidisciplinaryIntroduction
KevinLeyton-Brown,YoavShoham
2008
AConciseIntroductiontoMultiagentSystemsandDistributedArtificialIntelligence
NikosVlassis
2007
IntelligentAutonomousRobotics:ARobotSoccerCaseStudy
PeterStone
2007
Copyright© 2009byMorgan&Claypool
Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,ortransmittedin
anyformorbyanymeans—electronic,mechanical,photocopy,recording,oranyotherexceptforbriefquotationsin
printedreviews,withoutthepriorpermissionofthepublisher.
MarkovLogic:AnInterfaceLayerforArtificialIntelligence
PedroDomingosandDanielLowd
www.morganclaypool.com
ISBN:9781598296921 paperback
ISBN:9781598296938 ebook
DOI10.2200/S00206ED1V01Y200907AIM007
APublicationintheMorgan&ClaypoolPublishersseries
SYNTHESISLECTURESONARTIFICIALINTELLIGENCEANDMACHINELEARNING
Lecture#7
SeriesEditors:RonaldJ.Brachman,Yahoo!Research
ThomasDietterich,OregonStateUniversity
SeriesISSN
SynthesisLecturesonArtificialIntelligenceandMachineLearning
Print1939-4608 Electronic1939-4616
Markov Logic:
An Interface Layer for
Artificial Intelligence
Pedro Domingos and Daniel Lowd
UniversityofWashington,Seattle
WithcontributionsfromJesseDavis,TuyenHuynh,StanleyKok,LilyanaMihalkova,RaymondJ.
Mooney,Aniruddh Nath,Hoifung Poon,Matthew Richardson,Parag Singla,Marc Sumner,and
JueWang
SYNTHESISLECTURESONARTIFICIALINTELLIGENCEAND
MACHINELEARNING#7
M
&C Morgan &cLaypool publishers
ABSTRACT
Mostsubfieldsofcomputersciencehaveaninterfacelayerviawhichapplicationscommunicatewith
the infrastructure, and this is key to their success (e.g., the Internet in networking, the relational
model in databases,etc.).So far this interface layer has been missing in AI.First-order logic and
probabilisticgraphicalmodelseachhavesomeofthenecessaryfeatures,butaviableinterfacelayer
requirescombiningboth.Markovlogicisapowerfulnewlanguagethataccomplishesthisbyattaching
weights to first-order formulas and treating them as templates for features of Markov random
fields.MoststatisticalmodelsinwideusearespecialcasesofMarkovlogic,andfirst-orderlogicis
its infinite-weight limit. Inference algorithms for Markov logic combine ideas from satisfiability,
Markov chain Monte Carlo,belief propagation,and resolution.Learning algorithms make use of
conditional likelihood, convex optimization, and inductive logic programming. Markov logic has
been successfully applied to problems in information extraction and integration,natural language
processing,robot mapping,social networks,computational biology,and others,and is the basis of
theopen-sourceAlchemysystem.
KEYWORDS
Markovlogic,statisticalrelationallearning,machinelearning,graphicalmodels,first-
orderlogic,probabilisticlogic,Markovnetworks,Markovrandomfields,inductivelogic
programming,satisfiability,MarkovchainMonteCarlo,beliefpropagation,collective
classification,linkprediction,link-basedclustering,entityresolution,informationex-
traction,socialnetworkanalysis,naturallanguageprocessing,robotmapping,compu-
tationalbiology
vii
Contents
Acknowledgments................................................................ix
1 Introduction......................................................................1
1.1 TheInterfaceLayer.........................................................1
1.2 WhatIstheInterfaceLayerforAI?..........................................3
1.3 MarkovLogicandAlchemy:AnEmergingSolution...........................4
1.4 OverviewoftheBook.......................................................7
2 MarkovLogic....................................................................9
2.1 First-OrderLogic..........................................................9
2.2 MarkovNetworks.........................................................11
2.3 MarkovLogic.............................................................12
2.4 RelationtoOtherApproaches..............................................19
3 Inference........................................................................23
3.1 InferringtheMostProbableExplanation ....................................23
3.2 ComputingConditionalProbabilities........................................25
3.3 LazyInference............................................................29
3.4 LiftedInference...........................................................35
4 Learning........................................................................43
4.1 WeightLearning..........................................................43
4.2 StructureLearningandTheoryRevision.....................................52
4.3 UnsupervisedLearning ....................................................56
4.4 TransferLearning .........................................................62
5 Extensions......................................................................71
5.1 ContinuousDomains......................................................71
viii CONTENTS
5.2 InfiniteDomains..........................................................75
5.3 RecursiveMarkovLogic ...................................................84
5.4 RelationalDecisionTheory.................................................91
6 Applications .................................................................... 97
6.1 CollectiveClassification....................................................97
6.2 SocialNetworkAnalysisandLinkPrediction ................................98
6.3 EntityResolution ........................................................103
6.4 InformationExtraction ...................................................104
6.5 UnsupervisedCoreferenceResolution......................................106
6.6 RobotMapping..........................................................111
6.7 Link-basedClustering....................................................113
6.8 SemanticNetworkExtractionfromText....................................116
7 Conclusion ....................................................................121
A TheAlchemySystem...........................................................125
A.1 InputFiles...............................................................125
A.2 Inference................................................................127
A.3 WeightLearning.........................................................128
A.4 StructureLearning.......................................................128
Bibliography...................................................................131
Biography ..................................................................... 145
Acknowledgments
WearegratefultoallthepeoplewhocontributedtothedevelopmentofMarkovlogicandAlchemy:
colleagues, users, developers, reviewers, and others. We thank our families for their patience and
support.
TheresearchdescribedinthisbookwaspartlyfundedbyAROgrantW911NF-08-1-0242,
DARPA contracts FA8750-05-2-0283,FA8750-07-D-0185,HR0011-06-C-0025,HR0011-07-
C-0060 and NBCH-D030010,NSF grants IIS-0534881,IIS-0803481 and EIA-0303609,ONR
grants N-00014-05-1-0313 and N00014-08-1-0670, an NSF CAREER Award (first author), a
SloanResearchFellowship(firstauthor),anNSFGraduateFellowship(secondauthor)andaMi-
crosoftResearchGraduateFellowship(secondauthor).Theviewsandconclusionscontainedinthis
document are those of the authors and should not be interpreted as necessarily representing the
official policies,either expressed or implied,of ARO,DARPA,NSF,ONR,or the United States
Government.
PedroDomingosandDanielLowd
Seattle,Washington
Description:Most subfields of computer science have an interface layer via which applications communicate with the infrastructure, and this is key to their success (e.g., the Internet in networking, the relational model in databases, etc.). So far this interface layer has been missing in AI. First-order logic a