微觀課件秋季chapter 707

ChapterGeneralEquilibriumandWelfareChapterGeneralEquilibriumandWelfare1Chapter727.1Generalvs.Chapter727.1Generalvs.Partial7.2ParetoEfficiencyin7.3ParetoEfficiencyin7.4ParetoEfficiencyinExchangeand7.5CompetitiveMarketsandParetoReadingsaboutthisZhang:Chapter9,P274-ReadingsaboutthisZhang:Chapter9,P274-Nicholson:Chapter16,P421-Chapter17,P456-3Chapter747.1Generalvs.Chapter747.1Generalvs.Partial7.2ParetoEfficiencyin7.3ParetoEfficiencyin7.4ParetoEfficiencyinExchangeand7.5CompetitiveMarketsandParetoGeneralvs.PartialPartialequilibrium(局部均衡分析Generalvs.PartialPartialequilibrium(局部均衡分析AnalysisofasingleAssumesprice,quantityinteractionswithallothermarketssmallenoughtobeignoredGeneralequilibrium（一般均衡分析ConsidersallinteractionsamongSimultaneouslyobtainspricesinallConsistentrelationshipsamongallmarketsforallvariables(factors,incomes,etc.)5WhenisPartialEquilibriumOnlyinterestedWhenisPartialEquilibriumOnlyinterestedinasinglemarketorasingleConsumer’schoosehowtoallocatetakingpricesasFirm’schoosehowmuchtoproduce,takingdemandasgiven.Marketrelativelysmall–doesnotaffectotherpartsofeconomy.6WhenisPartialEquilibriumNotOneWhenisPartialEquilibriumNotOnemarkethassignificanteffectsonotherAlternateusesforfactorsofMarketislargerelativetorestofWhenthegoaloftheanalysisistoevaluatethewholeWhenwewanttostudyhowrelativepricesaredeterminedinamarket.7WhyDoWeUseGeneralPartialWhyDoWeUseGeneralPartialEquilibriumneglectsthewayinwhichchangesinonemarketaffectother(product/factor)markets.GeneralEquilibriumanalysesthewayinwhichthechoicesofeconomicagentsareco-ordinatedacrossallproductandfactormarkets.8Exchange2Exchange2individuals/consumers(Aand2products(XandProduction2products(Xand2factors(LandGeneral2individuals/consumers(Aand2products(Xand2factors(Land9EconomicEfficiencyandParetoOptimalityEconomicEfficiencyandParetoOptimalityHowtoevaluatethesituationofaresourceallocationoreconomicefficiency.WecanuseParetoEfficiencytoexpressParetoEfficientAnallocationofresourcesisparetoefficientifitisnotpossible(throughfurtherreallocation)tomakeonepersonbetteroffwithoutmakingsomeoneelseworseoff.EconomicEfficiencyandParetoTheParetodefinitionthenidentifiesparticularallocationasEconomicEfficiencyandParetoTheParetodefinitionthenidentifiesparticularallocationasbeing“inefficient”ifunambiguousimprovementsarepossible.Notice:thedefinitiondoesnotrequireinterpersoncomparisonsofutility.“Improvements（帕累托改進）aredefinedbyindividualsthemselves.Chapter7Chapter7ParetoEfficientinExchange:Twoconsumers,AandEndowmentsofParetoEfficientinExchange:Twoconsumers,AandEndowmentsofgoodsXandYB=(6,4)andωB=(2,TotalquantitiesavailableωXA+ωXB=6+2=8unitsofgoodωY+ωY=4+2=6unitsofgood Exchange:TheEdgeworthTheoryofExchange:TheEdgeworthTheoryofModeledusingEdgeworthShowsallpossibleallocationsoffixedquantitiesofgoodsXandYbetweenconsumersAandBStartwithinitialallocationendowments（稟賦Aftertrade,endupwithfinalTradedquantitiesmustbeHowtosetupEdgeworthLookattheHowtosetupEdgeworthLookattheworldfromIndividualA’sLookattheworldfromIndividualB’sCombineAandB’sworldstoformanEdgeworthbox2AB2 86Assume2AB2 86AssumeaworldwithnoproductionandwithfixedendowmentsofXandY(hencethelineontopofXandY).StartinganEdgeworthHeight46StartinganEdgeworthHeight4662WidthABXXEdgeworthBox:TheY64X(6,4)68EdgeworthBox:TheY64X(6,4)68EdgeworthBox:The22646(2,2)8EdgeworthBox:The22646(2,2)8EdgeworthBox:EndowmentAYABYYEEdgeworthBox:EndowmentAYABYYEOtherFeasibleAllocations（其他可能分配狀況(xA,YA)denotesanallocationtoOtherFeasibleAllocations（其他可能分配狀況(xA,YA)denotesanallocationtoconsumer(XB,YB)denotesanallocationtoconsumerFeasibleallocation+YBYA+ASo,allpointsinEdgeworthbox(includingthoseonboundary)FeasibleReallocations:OBBYAYAXEFeasibleReallocations:OBBYAYAXEIndifferenceCurveFromIndividualUUIndifferenceCurveFromIndividualUUIndifferenceCurveFromIndividualUUIndifferenceCurveFromIndividualUUEdgeworthYXAXEdgeworthYXAXPareto-improvingRe-allocationofPareto-improvingRe-allocationofendowmentimprovingwelfareofoneconsumerwithoutreducingwelfareoftheOnlyPareto-improvingreallocationswilloccurthroughvoluntarytrade（自愿交易）CanbeeasilyidentifiedonEdgeworthboxPareto-ImprovingAlltradesinsideblacklensarePareto-improvingtradesPareto-ImprovingAlltradesinsideblacklensarePareto-improvingtradesPareto-ImprovingTradebothA’sandB’swelfareSo,Pareto-improvementoverendowmentallocationPareto-ImprovingTradebothA’sandB’swelfareSo,Pareto-improvementoverendowmentallocationPareto-ImprovingNewgains-from-tradeissetofallfurtherPareto-ImprovingNewgains-from-tradeissetofallfurtherPareto-Optimality:Pareto-optimalorAllocationwhereconvexindifferencecurvesareOnlywayoneconsumer’swelfarePareto-Optimality:Pareto-optimalorAllocationwhereconvexindifferencecurvesareOnlywayoneconsumer’swelfarecanbeincreasedistodecreasethatoftheotherPareto-Optimality:BothAandBareworseoffAisstrictlybetteroffbutBisPareto-Optimality:BothAandBareworseoffAisstrictlybetteroffbutBisstrictlyworseoffBisstrictlybetteroffbutAisstrictlyworseoffBothAandBareworseoffPareto-Optimality:IdentifyallParetooptimalYXPareto-Optimality:IdentifyallParetooptimalYXPareto-Optimality:YXPareto-Optimality:YXPareto-Optimality:YXContractcurve-setofallParetooptimalallocationsPareto-Optimality:YXContractcurve-setofallParetooptimalallocationsCurve（契約曲線ThecurveconnectingallParetoefficientallocationsisknownasCurve（契約曲線ThecurveconnectingallParetoefficientallocationsisknownasthecontractAteachpointonthecontractcurve,theMRS’sforAandBareequal,i.e.=HowtoachieveParetoEfficiencyinAn“auctioneer”（拍賣者）adjuststheproductprices(PxandPyuntilthefollowingthreeconditionshold:HowtoachieveParetoEfficiencyinAn“auctioneer”（拍賣者）adjuststheproductprices(PxandPyuntilthefollowingthreeconditionshold:MRSMRSPPYYDemandforXDemandforYPareto-ImprovingThesetofPareto-improvingreallocationsYABYYXAXPareto-ImprovingThesetofPareto-improvingreallocationsYABYYXAXPareto-ImprovingParetooptimaltradesblockedbyYABYYXAXParetooptimaltradesPareto-ImprovingParetooptimaltradesblockedbyYABYYXAXParetooptimaltradesblockedbyPareto-ImprovingPareto-optimaltradesnotblockedbyAorBaretheCOREYABYYXAXPareto-ImprovingPareto-optimaltradesnotblockedbyAorBaretheCOREYABYYXAXTheCore（核）Core-TheCore（核）Core-setofallallocationsthatParetooptimalallocations,Welfare-improvingforbothconsumers,givenoriginalownendowmentsRationaltradeshouldachieveallocationinWhichcoreallocation?Dependsonallocationmechanism(competition,monopoly,negotiation,Chapter7Chapter7ParetoEfficiencyinProductionProductiveParetoParetoEfficiencyinProductionProductivePareto（生產(chǎn)的帕累托狀態(tài)Anallocationofresourcesisefficientinproduction(or“technicallyefficient”)ifnofurtherreallocationwouldpermitmoreofonegoodtobeproducedwithoutnecessarilyreducingtheoutputofsomeothergood.ParetoEfficiencyinProductionTwofirmsParetoEfficiencyinProductionTwofirmsproducetwoproducts(XandThefirmsusetwofactorsofproduction,(K)andlabourAssumefixedendowmentsofKand(Production)EdgeworthGoodYAtthe(Production)EdgeworthGoodYAttheGoodXContractCurveofYoucanjoinupalltheseformtheContractCurveofYoucanjoinupalltheseformtheContractCurveinThecurveconnectingallParetoefficientallocationsinproductionisContractCurveinThecurveconnectingallParetoefficientallocationsinproductionisknownasthecontractcurveinproduction.Ateachpointonthecontractcurve,theMRTS’sforXandYareequal,i.e.=HowtoachieveProductionEconomyAn“auctioneer”adjuststhefactorprices(Pl=wandPk=r)untilthefollowingthreeconditionshold:HowtoachieveProductionEconomyAn“auctioneer”adjuststhefactorprices(Pl=wandPk=r)untilthefollowingthreeconditionshold:YXrrDemandforLDemandforKChapter7Chapter7Wehavedescribedgeneralequilibriuminasimpleexchangeeconomy,thatensuresbothgoodsmarketsareinequilibrium.Wehavedescribedgeneralequilibriuminasimpleexchangeeconomy,thatensuresbothgoodsmarketsareinequilibrium.Wehavedescribedgeneralequilibriuminasimpleproductioneconomy,thatensuresbothinputmarketsareinequilibrium.Wewillnowlookatproductionandexchange…todoso,weneedfirsttodescribetheeconomy’sproductionpossibilities.FromContractCurveinProductiontoProductionPossibilityCurveFromContractCurveinProductiontoProductionPossibilityCurveProductionPossibilityYEachpointontheproductionpossibilityis(Pareto)ProductionPossibilityYEachpointontheproductionpossibilityis(Pareto)XProductionPossibilityY=xProductionPossibilityY=xProductionPossibilityinsidethecurveareYxProductionPossibilityinsidethecurveareYxProductionPossibilitiesyNotFeasiblebutxProductionPossibilitiesyNotFeasiblebutxProductionPossibilitiesMarginalrateoftransformationisthenumberofunitsofythatmustbegivenupinordertoproduceoneProductionPossibilitiesMarginalrateoftransformationisthenumberofunitsofythatmustbegivenupinordertoproduceonemoreunitofyxGeneralClaim:Inequilibrium,firmswillproduceGeneralClaim:Inequilibrium,firmswillproduceatthepointontheproductionpossibilitycurveatwhichMRT=IfMRT<Px/PyproducemoreXandlessIfMRT>Px/PyproducelessXandmore[Aside:=Px/PyMRTxy=GeneralTheslopeofthePPC=Px/PyyGeneralTheslopeofthePPC=Px/PyyxGeneralAtthispointwintofxandyYYyGeneralAtthispointwintofxandyYYyXxGeneralRecallMRSxy=YYXGeneralRecallMRSxy=YYXxGeneralMRS=MRT=GeneralMRS=MRT=GeneralThreeConditionsforGeneralGeneralThreeConditionsforGeneralFromContractCurvetoUtilityPossibilityFromContractCurvetoUtilityPossibilityYWYDXXYWYDXXGrandUtilityPossibilityGrandUtilityPossibilityWelfare(社會福利HowwillasocietychoosewhereWelfare(社會福利HowwillasocietychoosewheretobeontheUPF?Votingisawayofdecidingwhowhatofthenationalpie.Butthereproblems,e.g.,majorityvotingmaynotleadtoanequilibrium.DefineasocialwelfareSocialWelfareFunctions（社會福利函數(shù)W=W(UASocialWelfareFunctions（社會福利函數(shù)W=W(UAWissocialisA’sisB’sSocialWelfareFunctions（社會福利函數(shù)WhatformmightaSocialWelfareSocialWelfareFunctions（社會福利函數(shù)WhatformmightaSocialWelfarefunctionExamplesforasocietyofnSWW(U1(X),U2(X),L,Un(XX(X1/n,X2/n,L,Xn/Benthamite（邊沁主義者）orUtilitarian（功利主義者）社會福SW=U1+U2+...+SW=1U1+2U2+...+SW=min{U1,U2,...,Theaimistomaximisesocialzvope=SWSW SWuzvope=SWSW SWuSummary:ParetoTohavePareto-optimalityinSummary:ParetoTohavePareto-optimalityinproduction,mustbethecase…w/r=MRTSLKx=ThisimpliesthattheeconomymustproduceonthePPF.TohavePareto-optimalityinexchange,itmustbethecasethat……px/py=MRSXYA=Thisimpliesthattheeconomymustconsumeontheexchangecontractcurve.Pareto-optimalWhenweconsiderproductionconsumptiontogether,thereisathirdconditionPareto-optimalWhenweconsiderproductionconsumptiontogether,thereisathirdconditionforanoutcometobePareto-optimal.Therateatwhichtheconsumptionofonegoodcanbesubstitutedforconsumptionofanother,mustequaltherateatwhichtheproductionofonegoodcanbesubstitutedfort