经济学基础 13页

12SHORT-RUNECONOMICFLUCTUATIONS\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvParti:IS-LMModelandAD-ASModel\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvTheoriginofIS-LMmodel•IS-LMmodelisaboutthesimultaneouslyequilibriumsofgoods(services)marketsandassetmarket.•I:Investment;•S:Saving;•L:Moneydemanded;•M:Moneysuppliedt•TheIS-LMmodelwasdevelopedin1937byNobellaureateJohnHicks,whointendeditasagraphicalrepresentationoftheideasofKeynes.•Theimportantassumption:theeconomyisclosed.\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvTheIScurve:equilibriuminthegoodsandservicesmarket\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvTheIScurve:equilibriuminthegoodsandservicesmarket•Intheleft-handside,itisadeterminedprocessofrealinterestrateandmoneydemanded.•Inthisprocess,achangeofoutputYbringsacorrespondingshiftofsavingcurve,whichthenresultinanewequilibrium.\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvTheIScurve:equilibriuminthegoodsandservicesmarket•TheimplicationofIScurve:IScurveshowstherealinterestrate,r,forwhichthegoodsmarketisinequilibrium;so,atallpointsontheIScurvedesiredinvestmentequalsdesirednationalsaving.•Ingeneral,becauseariseinoutputincreasesdesirednationalsaving,therebyreducingtherealinterestratethatclearsthegoodsmarket,theIScurveslopesdownward.\nLiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvTheIScurve:equilibriuminthegoodsandservicesmarket•FactorsthatshifttheIScurve:LiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvLiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvAnincreaseinExpectedfutureoutputShiftstheIScurveUpReasonWealthUpGovernmentpurchases,GTaxes,TUpNochangeordownsi©）由si（c）uSl（demandforgoods。4Nochange:RicardianequivalenceDown:noRE,C],rjLiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvLiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvMPKExpectedtaxrateoncapital\nLiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvTheIScurve:equilibriuminthegoodsandservicesmarketLiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvLiTun.Ph.DinEcguiucn,SchoolTouriwManagEniBnt,SunY社一zenUrLLuerwrtvSaving,S;Investment,I4500Output,YRealmteTes-raa\nPh.DinEcgumicn.SchoolerfTouriwiiiManagEniBnt.Sun丫豪一鸵力UniuersrtvTheIScurve:equilibriuminthegoodsandservicesmarket•Insummary,forconstantoutput,anychangeintheeconomythatreducesdesirednationalsavingrelativetodesiredinvestmentwillincreasetherealinterestratethatclearsthegoodsmarketandthusshifttheIScurveup.\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvTheLMcurve:AssetmarketequilibriumDerivingtheLMcurve:assumption---Pconstant\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力Uniuerwrtv•Figure3\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvTheLMcurve:Assetmarketequilibrium•TheimplicationofLMcurve:LMcurveshowstherealinterestrate,r,forwhichtheassetmarketisinequilibrium;so,atallpointsontheLMcurvedesiredmoneydemandequalsdesiredmoneysupply.•Ingeneral,becauseariseinoutputincreasesdesiredmoneydemand,therebyincreasingtherealinterestratethatclearstheassetmarket,theLMcurveslopesupward.\nLiTun.Fh.DinEcdnumicn.School111fTouiiwmManagEniEnt.Sun丫家一二已力UniuerwrtvTheLMcurve:Assetmarketequilibrium•Themoneydemandfunction:Md=P^L(Y,r+7ce):NominaldemandorMd/P=L(Y,r+Ke):Realdemand.