chap011PerfectCompetition(M-Grow-Hill,微观经济学,

Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/IrwinPerfectCompetitionChapter11Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-2LaugherCurveQ.Howmanyeconomistsdoesittaketoscrewinalightbulb?A.Eight.Onetoscrewitinandseventoholdeverythingelseconstant.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-3PerfectCompetitionTheconceptofcompetitionisusedintwowaysineconomics.Competitionasaprocessisarivalryamongfirms.Competitionastheperfectlycompetitivemarketstructure.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-4CompetitionasaProcessCompetitioninvolvesonefirmtryingtotakeawaymarketsharefromanotherfirm.Asaprocess,competitionpervadestheeconomy.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-5CompetitionasaMarketStructureItispossibletoimaginesomethingthatdoesnotexist–aperfectlycompetitivemarketinwhichtheinvisiblehandworksunimpeded.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-6CompetitionasaMarketStructureCompetitionistheendresultofthecompetitiveprocessunderhighlyrestrictiveassumptions.Aperfectlycompetitivemarketisoneinwhicheconomicforcesoperateunimpeded.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-7APerfectlyCompetitiveMarketAperfectlycompetitivemarketisoneinwhicheconomicforcesoperateunimpeded.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-8APerfectlyCompetitiveMarketAperfectlycompetitivemarketmustmeetthefollowingrequirements:Bothbuyersandsellersarepricetakers.Thenumberoffirmsislarge.Therearenobarrierstoentry.Thefirms'productsareidentical.Thereiscompleteinformation.Firmsareprofitmaximizers.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-9TheNecessaryConditionsforPerfectCompetitionBothbuyersandsellersarepricetakers.Apricetakerisafirmorindividualwhotakesthemarketpriceasgiven.Inmostmarkets,householdsarepricetakers–theyacceptthepriceofferedinstores.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-10TheNecessaryConditionsforPerfectCompetitionBothbuyersandsellersarepricetakers.Theretailerisnotperfectlycompetitive.Astoreisnotapricetakerbutapricemaker.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-11TheNecessaryConditionsforPerfectCompetitionThenumberoffirmsislarge.Largemeansthatwhatonefirmdoeshasnobearingonwhatotherfirmsdo.Anyonefirm'soutputisminusculewhencomparedwiththetotalmarket.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-12TheNecessaryConditionsforPerfectCompetitionTherearenobarrierstoentry.Barrierstoentryaresocial,political,oreconomicimpedimentsthatpreventotherfirmsfromenteringthemarket.Barrierssometimestaketheformofpatentsgrantedtoproduceacertaingood.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-13TheNecessaryConditionsforPerfectCompetitionTherearenobarrierstoentry.Technologymaypreventsomefirmsfromenteringthemarket.Socialforcessuchasbankersonlylendingtocertainpeoplemaycreatebarriers.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-14TheNecessaryConditionsforPerfectCompetitionThefirms'productsareidentical.Thisrequirementmeansthateachfirm'soutputisindistinguishablefromanycompetitor'sproduct.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-15TheNecessaryConditionsforPerfectCompetitionThereiscompleteinformation.Firmsandconsumersknowallthereistoknowaboutthemarket–prices,products,andavailabletechnology.Anytechnologicaladvancementwouldbeinstantlyknowntoallinthemarket.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-16TheNecessaryConditionsforPerfectCompetitionFirmsareprofitmaximizers.Thegoalofallfirmsinaperfectlycompetitivemarketisprofitandonlyprofit.Firmownersreceiveonlyprofitascompensation,notsalaries.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-17TheDefinitionofSupplyandPerfectCompetitionIfallthenecessaryconditionsforperfectcompetitionexist,wecantalkformallyaboutthesupplyofaproducedgood.Thisfollowsfromthedefinitionofsupply.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-18TheDefinitionofSupplyandPerfectCompetitionSupplyisascheduleofquantitiesofgoodsthatwillbeofferedtothemarketatvariousprices.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-19TheDefinitionofSupplyandPerfectCompetitionThisdefinitionrequiresthesuppliertobeapricetaker(thefirstconditionforperfectcompetition).Sincemostsuppliersarepricemakers,anyanalysismustbemodifiedaccordingly.Copyright©2001byTheMcGraw-HillCompanies,Inc.Allrightsreserved.McGraw-Hill/Irwin11-20TheDefinitionofSupplyandPerfectCompetitionBecauseofthedefinitionofsupply,ifanyoftheconditionsarenotmet,theformaldefinitionof