The International Symposium on Practical Aspects of Declarative Languages (PADL)focusesonpracticalapplicationsofdeclarativelanguages. Thecollection ofpapersinthisvolumewaspresentedatPADL2001. Thesymposiumwasheld inLasVegas,Nevada,March11–12,2001. Fortypapersweresubmittedinresponsetothecallforpapers. Twenty-three paperswere?nallyselectedforpresentationatthesymposium. Thesymposium includedinvitedtalksbyJoeArmstrongofBluetail,RaghuRamakrishnanfrom theUniversityofWisconsinatMadison,andDavidS. Warrenfromthe State UniversityofNewYorkatStonyBrook. ThesymposiumwassponsoredandorganizedbyCOMPULOGAMERICAS (http://www. cs. nmsu. edu/~complog),anetworkofresearchgroupsdedicated topromotingresearchinlogicprogrammingandrelatedareas,bytheAssoc- tionforLogicProgramming(http://www. cwi. nl/projects/alp),theDepa- mentofComputerScience,UniversityofTexasatDallasandtheDepartment ofComputerScienceattheStateUniversityofNewYorkatStonyBrook.^ The supportofmanyindividualswascrucialtothesuccessofthissymposium. My thankstoGiridharPemmasani,SamikBasu,DivyangiAnchan,ShachiPoddar, and Shabbir Dahodwala for their help with organizing and managing the - viewingprocess. SpecialthankstoR. C. Sekarforsettingupandmanagingthe PADL2001 web site and to Gopal Gupta for handling all the organizational details. Manythankstotheprogramcommitteemembersforalltheirhelpin- viewingandtheiradvice. Finally,mythankstoalltheauthorswhotookinterest inPADL2001andsubmittedpapers. January2001 I. V. Ramakrishnan ProgramChair ProgramCommittee S. Antoy PortlandStateUniv. S. Debray Univ. ofArizona M. Fromherz XeroxPARC C. Geyer FederalUniversityofRioGrandedoSul,Brazil B. Goldberg NYU N. Heintze BellLabs,LucentTechnologies S. Krishnamurthi BrownUniversity L. Maranget INRIARocquencourt E. Meijer UtrechtUniversity G. Morrisett CornellUniversity U. Nilsson LinkopingUniversity C. Palamidessi PennStateUniv. E. Pontelli NewMexicoStateUniv. I. V.^ Ramakrishnan(PCChair) SUNYStonyBrook D. Sands ChalmersUniversityofTechnology R. Sekar SUNYStonyBrook D. Srivastava AT&TLabsResearch T. Swift SUNYStonyBrook K. Ueda WasedaUniversity R. Yap NationalUniversityofSingapore N-F. Zhou CUNYBrooklynCollegeandGraduateCenter Referees S. Antoy S. Krishnamurthi C. R. Ramakrishnan S. Debray L. Maranget D. Sands Frank G. Morrisett R. Sekar M. Fromherz K. NarayanKumar D. Srivastava C. Geyer U. Nilsson P. Swift B. Goldberg C. Palamidessi K. Ueda N. Heintze G. Pemmasani R. Yap O. Kaser E. Pontelli N-F. Zhou SponsoringInstitutions COMPULOGAMERICAS, http://www. cs. nmsu. edu/~complog AssociationforLogicProgramming, http://www. cwi. nl/projects/alp TableofContents AModelCheckerforValue-PassingMu-CalculusUsingLogic Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 C. R. Ramakrishnan DesignandImplementationoftheHigh-LevelSpeci?cationLanguage CSP(LP)inProlog. . . . . . . . . . . . . . . .^ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 M. Leuschel Frapp´e:FunctionalReactiveProgramminginJava . . . . . . . . . . . . . . . . . . . . . 29 A. Courtney FromSubjectDirectoriestoSubjectMeta-directoriesviaDeclarative Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 A. BrogiandG. Caruso ProgrammingGoal-DrivenWebSitesUsinganAgentLogicLanguage . . . . 60 M. Baldoni,C. Baroglio,A. Chiarotto,andV. Patti High-LevelServerSideWebScriptinginCurry . . . . . . . . . . . . . . . . . . . . . . . . 76 M. Hanus LogicProgrammingTechniquesforDynamicVRMLWebContent Generation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 A. GuptaandP. Tarau SoftConstraintsforSecurityProtocolAnalysis:Con?dentiality. . . . . . . . . .