Short Description Automata with substitutions, Fusion and Bindings, Models for Open π-calc

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DELIVERABLESUMMARYSHEETProjectNumber:IST-2001-33100ProjectAcronym:PROFUNDISTitle:ProofsofFunctionalityforMobileDistributedSystems

DeliverableNumber:3Duedate:Projectmonth36Deliverydate:March14,2005

ShortDescription:Automatawithsubstitutions,FusionandBindings,ModelsforOpenπ-calculusanddistinctions,ModelsofSpatialLogics.

SymbolicVerificationofSecurityProtocols.VerificationServicesandCaseStudies.

Partnersowning:DipartimentodiInformaticaUniv.Pisa,ItalyPartnerscontributed:Uppsala,FFCTLisbon,INRIA,PisaMadeavailableto:

1Contents1Overview32ScientificContributions32.0.1Task1.1:AutomatawithOperationsandSubstitutions.32.0.2Task1.2:ProofTechniques.................52.0.3Task1.3:PrototypeandCaseStudies...........52.1UpdateSecondYearReport.....................6

3Appendix:WP1ScientificContributions94Appendix:WP1UpdatedVersions10

21OverviewTheoverallgoalofthisWorkPackageistodevelopacomprehensiveautomata-likemodelthatsupportseffectivetechniquestospecifyandverifypropertiesofnetworkapplications.TheactivitiesonTask1.1.(Automatawithoperationsandsubstitutions)wereexpectedtobecompletedbytheendofthesecondyear.However,wemodifiedourinitialplansandwecontinuedthemalsointhethirdyear.Hence,foryear3thespecificobjectiveforTask1.1includeautomatawithsubstitutions,higherorderabstractsyntaxandfunctorialsemantics,and(bialgebraicandfunctorial)modelsfordistinctions(openπ-calculus,fusion)andmodelsforspatiallogics.ForTask1.2wecontinuedthedevelopmentofprooftechniques(typicallyofsecurityprotocols)basedonsymbolicexecution.Task1.3.wasconcernedwithextendingtheProfundistoolkitinfrustructure(thePweb).Moreover,wetoassessourverificationinfrastructurewefocussedonsomecasestudies.ThisdeliverableincludesthescientificcontributionsofthethirdyearforWP1.Thedeliverableconsistsofashortpresentationofthecontributionsandofseveralappendiceswiththecontributedpapers.

2ScientificContributionsTheresearchactivitiesofalltaskshaveadvancedwell,providingsomeresultsintermsofbothpublicationsandexperimentation.Hereafter,wewillbrieflysummarizetheresultsoftheresearchactivitiesofthethirdyearforeachofthethreetasks.

2.0.1Task1.1:AutomatawithOperationsandSubstitutionsAutomatawithsubstitutionsandBialgebraicmodelsTheformulationofHD-automataasthebasicmodelfornamepassingprocesscalculihasbeenfurtherdeveloped.Duringthethirdyear,wedeveloped[13]ageneralframe-worktodescribethesymbolicsemanticsofnominalcalculi,whereinputsarerepresentedasvariableswhichareinstantiatedonlywhenneededasithappensinlogicprogramming.TheapproachwefollowreliesonthenotionsofreactivesystemandofobservableborrowedcontextsintroducedbyLeiferandMilnerandfurtherdevelopedbySassone,LackandSobocinskiusingG-categoriesandadhesivecategories.Thereductionsemanticsofreactivesystemsisextendedinordertointroduceasborrowedcontextsboththevariableinstantiationsneededinthetransitionsandtheordinaryπ-calculusactions.Theproposedmodelcannaturallydescribeinteractionswithbindingmechanismscanbeconvenientlyappliedtohandlewebservicediscoveryandinvocations.Bialgebraicmodelsofprocesscalculienjoythepropertythatbisimilarityisacongruence.Indeed,theuniquemorphismtothefinalbialgebrainducesabisimilarityrelationwhichcoincideswithobservationalequivalenceandwhichisacongruencewithrespecttotheoperations.However,theapplicationofthebialgebraicapproachtopro-cesscalculiwithstructuralaxioms(e.g.namepassingprocesscalculi)ismore

3problematic,becauseoftheinteractionbetweenaxiomsandinferencerules.In[16],weintroduceageneralapproachtoliftcalculiwithstructuralaxiomstobialgebras.Inorderfortheliftingtohold,twoconditionsarerequired:thetran-sitionrulesofthecalculusareintyftformatandtheaxiomsbisimulatewithrespecttothelts.In[17]weprovideacompositionalcoalgebraicsemanticsoftheFusioncalculus.Inourmodel,theuniquemorphismtothefinalbialgebrainducesabisimilarityrelationwhichcoincideswithhyperequivalenceandwhichisacongruencewithrespecttotheoperations.

FunctorialSemanticsforNominalCalculiWehaveheretwolinesofre-search,allaimingatthedevelopmentofabstractmodelsfornomicalcalculi.ThefirstlineofresearchdevelopedatUppsalaconcernsthedevelopmentoffunctorialmodelsfornames.In[15]thetechniquesofhigherorderabstractsyntaxandfunctorialoperationalsemanticshavebeenextendedtogiveacleanpresentationofopenbisimularity.Akeyresultshowsthatopenbisimulationrequiresustomovefromtheusualsemanticdomainofpresheavesoversubcate-goriesofSettopresheavesoversubcategoriesofRel.In[18]acategorytheoreticmodelwhereboth“variables”and“names”,usuallyviewedasseparatenotions,havebeeninvestigated.Theproposalconsidersfunctorsoverthecategoryofirreflexive,symmetricfiniterelations.Themodelspreviouslyproposedforthenotionsof“variables”and“names”embedfaithfullyinthenewone,andini-tialalgebra/finalcoalgebraconstructionscanbetransferredfromtheformerstothelatter.ThesecondlineofresearchdevelopedinPisa[14]aimsatpro-vidingageneralframeworktorelatethedifferentabstractmodelsofnominalcalculi,namely(pre)sheafcategories,nominalsets,permutationalgebrasandnamedsets.Therelationshipsamongthesemodelshavebeenstudiedandtheproposedframeworwallowsonetotransfertechniquesandconstructionsfromonemodeltotheother.