微观经济学-中山大学.ppt

MICROECONOMICSClassroom Lecture Notes(3 credits,as of 2004)1basedonHalR.VariansIntermediate Microeconomics,SixthEdition,referringtoPindyckandRubinfeldsMicroeconomics,FourthEdition.2Chapter 0 3Thesourceofalleconomicproblemsisscarcity.4Problemoftrade-off,andchoice.Economics,asa way of thinking,asadismalscience.Problems-solutions-hiddenconsequences.5Main decision-making agents:1 individuals(household),2 firms,and3 governments.6Objects of economic choice are commodities,including goods and services.7Main economic activities:Consumption,Production,andExchange.8Microeconomics and macroeconomics:toshowthemarketmechanism(theinvisible hand),tosupplementit.9The circular flow of economic activities.productmarketfactormarket10Theproduct marketandthefactor market.Themarketrelationismutualandvoluntary.Positive issues andnormative issues.11Marginal analysislRelationsbetweenlTotal magnitudes,lAverage magnitudes,andlMarginal magnitudes.121,MMistheslope of theTMcurve;2,AMistheslope of the rayfromtheorigintothepointattheTMcurve;TMMM(x*)AM(x*)x*x13 3,TMincreasing(decreasing)ifandonlyifMM0(MMAM(MM0.lThusboththeincomeoffercurvesandtheEngelcurvesareallraysthroughtheorigin.76lExample:lQuasilinearpreferencesleadtovertical(horizontal)incomeoffercurvesandvertical(horizontal)Engelcurves.77Chapter 8SlutskyEquation78lHow the optimum moves when the price of a good changes?79lDecomposition:lthetotaleffect=thesubstitutioneffect+theincomeeffect.lp13980lThepivotgivesthesubstitutioneffect,ltheshiftgivestheincomeeffect.lP103andp13781lSlutsky identity,pivotingthe budget line aroundtheoriginalchoice.Fig.lHicks decomposition,pivoting the budget linearoundtheindifferencecurve.Fig.82Chapter 9 BuyingandSellingforaconsumerwithanendowment 83x1x1x2p111Net and gross demands,netsupply.Offercurveanddemandcurve.p16484lLabor supplyp174$LeisureRLaborWLeisureE85Chapter 10IntertemporalChoice86lSuppose for example in a 3-periodmodel,theconsumptionisckandtheinterestrateisrkinperiodk,lthen the present value of theconsumptionsislc1+c2/(1+r1)+c3/(1+r1)(1+r2).lp19087Chapter 12Uncertainty88Utilities and probabilities.lExpected utility functions,or von Neumann-Morgenstern utility functions.lTheyareindifferentuptolanypositiveaffinetransformation.l(affinetransformation:y=a+bx).89lRisk aversion and riskloving.Concavevsconvexutility.Thesecond derivatives.$UU90Chapter 14Consumers surplus91123456 pr1r2r3r4r5r6ConsumersSurplusp250消费者得益总收益92Producers surplus p259ProducerssurplusSupplycurveQP*Q*P93QSupplycurveChangeinproducerssurplusRTQQPPP94The water-diamond paradoxPdPwQ95Calculating gains and lossesChangeinconsumerssurplusBT96Chapter 15 Market Demand97Onecanthinkofthemarketdemandasthedemandofsome“representativeconsumer”98 Adding up demand curves:The horizontal summation principle.99+=Horizontal summation100PRICEDEMANDCURVED(p)QUANTITYIt is the sum of the individual demand curveThe market demand curve101Theprice elasticity of demand:=(q/q)/(p/p)=(p/q)/(p/q),or=(dq/q)/(dp/p)=(p/q)/(dp/dq)=slopeofray/slopeofcurve.102Agoodhasanelastic(inelastic,unitary)demandif|1(|1=1f(tx)(1/2,p=0,1ifq=1/2,0ifq1/2,q=0,1ifp=1/2,1ifp1/2.q11pN0210lMethod of response functions:The intersections of response functions give Nash equilibria(p*,q*)=(1/2,1/2)in example)lNash Theorem:There is always a(maybe“mixed”)Nash equilibrium for any finite game211lSequential games.lGamesinextensive form versusinnormal form.212BattleofSexesagainBoyGirlBalletBalletBalletSoccerSoccerSoccer(1,2)(-1,-1)(0,0)(2,1)213StrategiesasPlansofActions.Boysstrategies:Ballet,andSoccer.GirlsStrategies:Balletstrategy;Soccerstrategy;Strategytofollow;andStrategytooppose.214Chapter 28Exchange215Partial equilibrium and general equilibrium216Edgeworth box p497 lApureexchangemodeloftwogoods,twoconsumerswithfixedendowmentsw.217lRegion of mutual advantages.lParetosetandthecontract curve.lBargainingforrelativeprices.lGrossdemand x(p),lNetorexcess demandz(p)=x(p)-w(p).218Person BPerson AxA1wA1Endowment wA2xA2GOOD 2GOOD 1xB1wB1xB2wB2M219EndowmentPersonBsindifferencecurveAParetoefficientallocationPersonAsindifferencecurveContract curvePerson AGOOD 1GOOD 2Person B220lFromdisequilibriumtothecompetitiveequilibrium.Whichgoodistoocheap?lOffer curve approach.lTheexistenceproblemofequilibrium.221Asind,curvesBsind.curvesAsoffercurveBsoffercurveGood1isToocheapEquilibriumpriceWE222Chapter 29Production223The Robinson Crusoe economy Production functionIndifference curvesLaborL*C*Coconuts224Production possibilities setF*C*COCNUTSFISHPRODUCTION POSSIBILITIES SETSLOPE=MARGINAL RATE OF TRANSFORMATION(Two outputs case)225Trade leads toSeparation of prod.and coms.(P/C),Production specialization(A P),andWealth improvement(A C).APC226Heckscher-Ohlin theoryoninternationaltrade,undermanyidealizationassumptions.227l*Costs of exchange.l*Price difference between selling and buying.Fig.l*GATT and WTO.228Chapter 30Welfare229The social preference.Two kinds of voting:majority,and rank-order.230The social welfare function.lBenthamite:W(u1,u n)=a 1u 1+a n u n.lRawlsian:W(u1,u n)=min u1,u n.231Three requirements on a social decision mechanism:1,It should be complete,reflexiveand transitive;2,If everyone prefers X to Y,then the society should prefer X to Y;3,The preferences between X and Y should depend only on how people rank X versus Y,and not on how they rank other alternatives.232Arrows Impossibility Theorem lIf a social decision mechanism satisfies properties 1,2,and 3,then it must be a dictatorship:all social rankings are the rankings of one individual.233Chapter 31Externalities234Thelackofmarketsforexternalitiescausesproblems.235Withexternalities,themarketwillnotnecessarilyresultinaParetoefficientprovisionofresources.236However,someothersocialinstitutionscanmimicthemarketmechanism.237The model of smokers and nonsmokers(showingexcellentanalysistechniques).238Person APerson BSMOKEMONEYAsindifferencecurvesPossible equilibrium XPossible endowment EPossible endowment EPossible equilibrium XBadGood239Thepracticalproblemswithexternalitiesgenerallyarisebecauseofpoorlydefinedpropertyrights.Caose Theorem240Chapter 35 AsymmetricInformation241Commonknowledgeandprivateinformation.ThelatterleadstoAsymmetricinformation,orAsymmetryofinformation.242QualityDensityAkerlof model:the market for lemons.243Adverse selectionasahidden informationproblem.Moral hazardasahidden actionproblem.244SignalingTworolesofeducation:ToraiseandtodistinguishProductivitiesSpencemodel245$C(Y)forLwagesystemC(Y)forHY*YBestChoiceofL,andofH246Graphtoshowseparating equilibriaandpooling equilibria.247ENDandThanks248