上市公司的优缺点

上市公司的优势上市，是指股份有限公司在证券交易所公开发行股票后并公开上市交易。公司上市解决了企业发展所需要的资金，为公司的持续发展获得稳定的长期融资渠道，并借此可以形成良性的资金循环，可以在更广阔的范围内进行融资，从而扩大公司的资本金规模，进而扩大生产，提高盈利空间，并且上市公司股票融资是不用向投资者退还本金的，盈利了就分红，亏了就由股东和公司一起承担亏损。而非上市公司就只能通过借贷的方式来融资，有借就有还，非上市公司因此会承受很大的财务负担，增加企业经营的风险。成为公众l夀大提高知名度（媒体给予一家上市公司的关注远远高于非上市企业），同样可获得名牌效应，积聚无形资产。因为一上市，好多机构投资者就会研究，好多股民也会关注，而且只要上市，也就证明公司的注册资本、人员、管理水平等已上了一个台阶，比较规范，社会不相关人士都会增加对上市公司的信任度。上市公司的知名度会引起社会和媒体的高度关注，可以促进对企业的监督和管理作用，从而促进企业管理水平进一步提高，同时也可以把更优秀的人才吸引到企业来，为企业的发展注入更强大的动力。上市公司可以增大与其他知名企业的合作空间，进行强强合作，做大做强企业，如江苏大明与山西太原不锈钢厂的合作就是一个很好的典范。太钢非常愿意与大明进行战略合作，只要大明在国内某地设立子公司），太钢就愿意加盟入股。如最近大明与太钢合作在太原投资设立了太原太钢大明加工中心，该项目是江苏大明金属制品有限公司与太钢合资兴建的现代化钢铁综合服务中心。项目将依托太钢的生产能力和品牌优势，引进国际一流的加工设备及工艺，运用先进的创新型加工中心运营管理模式，打造以不锈钢深加工为主的钢铁服务型制造企业，成为钢铁产业链增值、不锈钢产业集成化发展的示范基地，项目建成后将为大型化工设备、桥梁结构、核电风电、轨道交通、特种船舶制造、工程机械等新兴领域提供配套服务。预计到2015年，实现不锈钢深加工量30万吨，碳钢20万吨。同时大明与太钢合作准备在武汉成立加工中心，预计明年5月开工建设，目前正在做可行性报告及公司营业执照注册等工作。从产业竞争角度来讲，一方面上市可以支持企业更快速地成长以取得在同行业领先的时机，另一方面，如果同行竞争者均已上市，企业同样需要充足资本与竞争对手对抗。上市也有一定的负面之处。首先每季度需要公布上市公司的财务报表及投资项目等，上市公司需要让股民知道拿着这些钱干什么。同时竞争对手也会看到上市公司的这些数据，因此保密性不强。其次上市会造成控制权失控。一上市随着时间的推移，上市公司的股份会变成全流通，这个时候一些有钱人就会轻而易举的把上市公司买走，让上市公司改名换姓。SearchImagesVideosMapsShoppingHYPERLINtp:///?hl=en&tab=TT"TranslateMore▼TranslateFrom:EnglishTo:Chinese(Simplified)EnglishSpanishFrenchTradeEquilibriumPrice

Itiscrucialtonotethattheimportdemandandexportsupplycurvesarenotthemselves

typicaldemandandsupplycurves.Eachofthemalreadyhaswithinitawholestructureof

productionanddemand.

RealIncomes,Production,ElasticitiesandtheTradePattern(appendix)

[ThefollowingisbasedontheappendicesofCavesandJones.]

Wewouldliketobeginbysettingoutthesourcesofwelfarecharges.Afirstexaminationshows

thatthesecancomeaboutdueto(1)changesinthetermsoftrade,or(2)endowmentchanges.

Therelevantexpression,whereRYreferstorealincomeinunitsoftheYgood:

Thisformidable-lookingexpressionactuallyhassomeintuitivecontent.Wehavechosento

measurewelfareintermsofyourrealconsumptionmeasuredinunitsoftheimportableYgood.

Notsurprisinglythen,thechangeinwelfareisgivenbythechangeinconsumptionthatis

attained--viz.PdDX+dDY(notethatthepriceconvertsunitsofXinto“real”terms,i.e.unitsof

Y).Thefinalexpressionofthishastwoterms.Thefirstisa“termsoftrade”effect.Notingthat

whenpˆ−1>0thenthepriceoftheimportablehasrisenrelatively,orequivalentlythetermsof

tradehaveworsened,wearenotsurprisedtofindthatthislowerswelfare.Thesecondtermis

lookingattheeffectsofsmallshiftsinourproductionbundle.Assumingthmaintainfull

employment,soremainonthePPF,thefirstordereffectofthesechangesiszero.Thereasonis

thatwewerealreadyatanoptimum,soalongthePPFMRT=dY/dX=-P.Butsimply

multiplyingandrearrangingthenshowsPdX+dY=0.[ThemoreadvancedstudentmaygnizethisasanexampleoftheWong/Vinerenvelopetheorem.]Whenthetermsoftradechange,whathappenstothedomesticdemandforimports?Thisisa

complicatedquestion.Wehavetoconsidersubstitutioneffectsandincomeeffectsindemand,as

wellasanyinducedeffectsonsupply.Theexpressionwhichwewillderivereflectsallofthese:

Ourdecisionsaboutimportsandexportsareintimatelylinkedbytherequirementof

balancedtrade.Whatdoesthissuggestabouttherelationoftheelasticitiesmportdemandand

exportsupFirstletusrecallthedefinitionsofeachoftheseterms:

ElasticityofimportdemandWewouldliketohaveanideahowthetermsoftradeadjusttoexogenouschanges

(anythingbutprices)inimportdemandsinthetwocountries.Theresultthatwewillderiveis

thatthetermsoftradewillturnagainstwhicheverhasthelargerproportigrowthinimport

demandatunchangedprices:

III.TheRicardianModelInthtchapterweestablishedanimportantprinciple:Ifautarkyrelativepricesdiffer,

itispossibleforcountriestotradeatanintermediatepriceratiosuchthatbothmaygain.Our

developmentoftheworldequilibriumwasinverygeneraltermsbasedondemandandsupplyin

eacntry.Howeveritwasleftunexplainedwhyautarkypricesshoulddiffer.Thepresent

chapterdevelopstheRicardianmodeloftrade,andusestheconceptofcomparativeadvantage

asthebasisoftrade.WewillseethatintheRicardianmodel,thiscomparativeadvantagederives

fromunderlyingdencesinthetechnologyavailabletoeachcountry.

ivationoftheRicardianPPF

Onefactor(labor)infixedsupply

TwoGoods:XandY

Thetechnologyisfullydescribedbytheconstantunitlaborinputs:aLXandaLY

Factormarketclearingrequires:

MRT=aLX/aLYdefinesthemarginalrateoftormation,whichtellshowmuchYmustbucedtoproduceonemoreunitofX(notethatitisconstanthere).[seeFigure1]

AutarkyEquilibriuminaRicardianWorld

Wewillassumehomogeneoushomotheticpreferencessothatwecanusetheconstructofa

singlerepresentativeconsumer.

Assumingthatbothgoodsareprodutheoptimalityconditionsinacompetitiveeconomy

insurethat:AbilitytoTransform

MRS=[∂U/∂X]/[∂U/∂Y]

WillingnesstoSubstitute

Homogenerencesmeanseverybodyinthesocietyhasthesamepreferences.

HomotheticpreferencesmeanthatforagivenrelativepriceP,theproportioninwhichthegoods

areconsumedisindependentofthelevelofincome.[Theseallowustoputasideforthemoment

problemsofincomedistribution.]

RicardianSupplyandDemand

Thepricesofoodsproduceddependonlaborcosts.Ifanypricewasstrictlyaboveitslabor

costs,thenassumingagiveeandfixedinputcoefficients,wecouldhaveinfiniteprofitsby

expandingproductfthatgoodtoaninfinitelevel.Thustheassumptionofcompetitionand

finiteproductionlsinsuresthatthepricemustbelessthanorequaltothelaborcosts;thatis:

PX≤waLX

andPY≤waLY

(equalityifactuallyproduced)

Ifbothgoodsareproduced,itfollowsthat:

P=PX/PY=(waLX)/(waLY)=aLX/aLY=MRT

ScandrawtheRicardianSupplyCurvesforXandY.Notethat,theautarkypricehasbeen

determinedevenbeforeconsideringdemand.Thedivisionofoutputbetweenthetwogoods,then

willcorrespondtothatdemandedatthesupply-determinedprice.ComparativeAdvantage

Whydocountriestrade?Whatdetermineswhichcountriesproducewhichgoods?Afirst

ideamightoccur:sincelaboristheonlyinput,homeshouldproducethosegoodswhichitcan

producewithlesslaborthantheforeigncountry.Itshouldimporttheothergoods.Thisheso-

calledPrincipleofAbsoluteAdvantage.Bythisprinciple,ifaLX<aLX*thenweshouldexport

goodX.Butisthisanadequatecharacterizationofthedeterminantsoftrade?Whatshould

happenifthehomecountryhasanabsoluteadvantageinproducingeverygood?Inthiscase,

aLi<aLi*forallgoodsi.Shouldtheytradeatall?

Toanswerthis,wemustturntothePrincipleofComparativeAdvantage.Thisis

arguablythemostimportantresultininternationaltradetheory,andsomustbestudiedclosely.

RecallthatwehavealreadydefinedthemarginalrateoftransformationasMRTaLX/aLY.

WewillsaythathomehasacomparativeadvantageintheproductigoodXjust

when:Notethatintheautarkyequilibrium,wehadtheconditionthatP=MRT,soalsointheforeign

countrywehadP*=MRT*.Thus,recallingthatP=PX/PY,wehaveacomparativeadvantagein

goodXwhenP<P*,thatiswhenwehavealowerautarkyrelativepriceofgoodX.

Thismayseemabithardtofollow.ButthebasicideaissiWearetheively

efficientproducerofX.Whenourautarkypriceislower,thismeansthatwehavetogiveupless

YtogetonemoreunitofXthanistrueintheforeigncountry.Conversely,iftheforeigncountry

weretduceoneunitlessofX,theycouldusetheextralabortoproducemoreYthanwe

gaveup.Intuitively,thisextraamountofYcouldbedividedupandbothwouldbebetteroff.

ComparativeAdvantage:AnExample

Herehomehasanabsoluteadvantageineachgood(check!).Howeveritscotiveadvantage

liesingoodX,since:Thusfromanautarkyposition,ifhomeproducedonelessY,itcouldproducetwomore

X.IfforeignproducedoneleitcouldproduceoreY.Thenetgaintotheworldof

shiftingthesiteofproductionisoneXandone-halfY.Bothcouldbemadebetteroff.

Note,then,absoluteadvantageisnotanadequatedeterminantofthepatternoftradehoughhomehasanabsoluteadvantageintheproductionofgoodY(aswellasgoodX),it

doesnotexportY.ThereasonisthatinspiteoftheabsoluteadvantageinY,ithasacomparative

disadvantageinY.

DerivatitheRicardianWorldProductionPossibilitiesFrontier

TheworldPPFshowsthemaximumblecombinationsofXagiventhe

availabletechnologyandlaborsupplies.AcombinationofXandYissaidtobethemaximum

feasibleifitisnotpossibletoproducemoreofonewithoutproducinglessoftheother.Theseare

alsocalledpointsoductionefficiency.

IfeachcountryisonitsPPF,doesitfollowthattheworldisontheworldPPF?No!It

maybethatthedistributionofproductionacrosscountriesisaccomplishedinefficiently.Insuch

acase,byshiftingthesiteofproductionofeachgoodtothecountrywithcomparativeadvantage

ofthatgood,wecanincreasetheavailabilityofsomegoodswithoutreducingtheavailabilityof

others.Thatis,wecanmovetowardsapointofworldproductionefficiency.

WewouldliketoderivetheworldPPF.Twopointsareeasilyderivable,namelythose

whenbothcountriesproduceonlyX,oronlyY.Inthiscase:

Toproceed,wemustknowthepatternofcomparativeadvantage.Suppose,asbefore,thathome

hasparativeadvantageingoodX.ThenMRT<MRT*.ThusifanyXatallshouldbe

produced,itshouldbeproducedinthehomecountry.Thus,startingfromapositionwhereonly

Yroduced,havethehomecountryproduceoneunitofX;theamountofYwehavetogive

upisexactlyMRT(recallthatishowwedefinedit!).Itisobviousthatwewouldhavethehome

startproducingXfirst,sincethefactthatithasalowerMRTsthatwehavetogiveupless

YforthatfirstunitofX.Note,though,thatsihelaborinpquirementsareconstantfor

eachcountry,thesamemustbetrueoftheirratio,theMRT.Thatis,foreachextraXwe

produce,wehavetogiveupMRTunitsofY.Thiscontinuestobetrueupuntilthepointthat

homeiscompletelyspecializedinX.IfwewanttheworldtoproduceyetmoreX,thenthe

foreigncountrywillhavetostartproducingit.But,nowthattheforeigncountrystartstoproduce

it,wehavetogiveueYtogetaunitofX,sinceMRT*>MRT.

NotethatifactualproductionistotheleftofthekinkintheworldPPF,thentheprice

undertradeisequaltothehomeautarkyprice:PT=PA=MRT.Ifweactuallyproducetothe

rightofthekink,thenPT=PA*=MRT*.Ifweactuallyproduceatthekink,thenallthatwecan

sayisthatthetradepriceisintherange:PT∈[PA,PA*].TodeterminetheactualpointontheworldPPFwherewewillproduce,wehavetolook

atworlddemandandsupply.Asbefore,assumeMRT<MRT*,andthepricesarePPX/PY.

Notethattheworldsupplycurveisinthenatureofastepfunction.Thiscorrespondstothe

conditionthatacountrywillproducebothgoodsonlyifP=MRTinthatcountry.Thusthe

horizontalsectionsoccuratthelevelsatwhichP=MRTintherespectivecountries.Wecanthen

definethreeregionsinwhichbothgoodsaresupplied.Atapriceequaltothehomeautarky

price,PT=MRTonlyhomewillproduceX(althoughitmayproducesomeYll);foreign

willspecializeinY.AtapricesuchthatMRT<PT<MRT*,bothcountriesspecialize--homein

goodXandforeigningoodY.AtatradepricesuchthatPT=MRT*thehomecountrywill

specializeingoodXandtheforeignwillbewillingtoproduceanyfeasiblecombinationofgood

XandY.Ofcourse,giventhesupplyconditions,thepricesandquantitiesdependonthedemand

conditions.However,notethatsmallshiftsindemandaffectproductionlevelsonlywhenoneof

thecountriesisproducingbothgoods.Further,inthiscase,thepriceiswhollyunaffected.Onthe

otherhand,ifbothcountriesarecompletelyspecialized,thensmallshiftsindemandleadtono

changeinproductionlevels,onlyachinthepricelevel!RicardianGainsFromTrade

Solongasthetradepricesdifferfromautarkyprices,therearegainstotrade.Ingeneral,

thegainswillbelargerthelargerthedivergence.

RelativeWagesinaRicardianWorld

TheRicardianmodelcanbeusedtotakeafistlookatwhatmightgiverisetothe

observeddistributionofwagesintheworld.

Ifbothcountriesspecialize,whichoccurswhenMRT<PT<MRT*,itmustbetruethat

PX=waLXandPY=w*aLY*.

Thisimpliesthatw/w*=[PX(1//[PY(1/aLY*)].Notethat1/aLXisthemarginal

productoflabor,soPX(1/aLX)givesthevalueofthemarginalproductforgoodX.Thustheratio

ofwagesbetweenthetwocountriesequalstheratioofthevalueoftherespectivemarginal

products.NotethatashiftofdemandthatraisedP=PX/PYyetstillleftproductioncompletely

specializedwouldraisehomerelativewages.

Wecansayabitmoreaboutrelativewagesinthisfirstcase.Solongasthetradeprices

are(weakly)betweentheautarkyprices,wecangiveaboundforrelativewages(alsoknownas

thefactoraltermsoftrade):Ifhomespecialized,butforeignot,thenitmustbethecasethat:

PX=waLX=w*aLX*andsow/w*=aLX*/aLX.

Thatis,hererelativewagesarefixedwhollybythetechnicaldifferencesinthegoodproducedin

common.Thisuesolongasonedoesnotspecialize.

SmallRicardianEconomyCapableofProducingNGoods

Bydefinition,asmallRicardianeconomyfacesfixedpricesforitsoutput.Evenifitis

capableofproducingNgoods,itwillspecializeinone(orseveralintheknife-edgecaseofatie)

forwhichthereisthelargestvalueofthemarginalproduct:Pi(1/aLi)=VMPi(recall1/aLiisthe

marginalproductinthei'thgood.TherewillbeatieifandonlyifPi/Pj=aLi/aLj.

NoticethatthissuggeststhatifweactuallylivedinaRicardianworldtherewouldlikely

beaverhdegreeofspecialization.AsalwaysinaRicardianmodel,wehavethetechnical

coefficients(herethelaborinputrequirements)independentofthelevelofoutputoassumedtobehomogeneousandperfectlymobiledomestically.

TechnicalProgressinaRicardianModel&DistributionoftheGains

Bydefinition,asmallRicardianeconomyfacesfixedpricesforitsoutput.Evenifitis

capableofproducingNgoods,itwillspecializeinone(orseveralintheknife-edgecaseofatie)

forwhichthereisthelargestvalueofthemarginalproduct:Pi(1/aLi)=VMPi(recall1/aLiisthe

marginalproductinthei'thgood.TherewillbeatieifandonlyifPi/Pj=aLi/aLj.

NoticethatthissuggeststhatifweactuallylivedinaRicardianworldtherewouldlikely

beaveryhighdegreeofspecialization.AsalwaysinaRicardianmodel,wehavethetechnical

coefficients(herethelaborinputrequirements)independentofthelevelofoutput.Laboris

assumedtobehomogeneousandperfectlymobiledomestically.

TechnicalProgressinaRicardianModel&DistribuoftheGains

Letfivegoodsbeproduced:goodsonetothreeathomeandfourandfiveabroad.Supposethere

istechnicalprogressingoodone(i.e.aL1falls).Supposefurtherthatwisfixed(sopricesof

goodstwoandthreeared).Whatwillhappentothewelfareofthetwocountries?

1.IfP4andP5remainunchanged,bothbenefitaswageratesarethesameandP1has

fallen.

2.IfP4andP5rise,saybecausedemandforgoodoneisinelastic,theforeigncountrywill

definitelygain,butitispossibleherethatthehomecountrywilllose.[Jones80-81saysthat

thereisnecessarilyalosstohomeifconsumptionisinfixedproportions].

3.IfP4andP5fall,thenhomemustgain,butforeigncouldgainorlose.Thismightbethe

case,say,ifgoodoneisasubstituteforgoodsfourandfive.

NontradedGoodsintheRicardianSmallOpenEconomy

Nontradedgoodsarethoseforwhichtransportcostsmaketradeinsuchgoods

prohibitivelycostly(e.g.land,haircuts,etc.].Asbefore,thesmallopeneywillproduce

onlythattradedgoodforwhichPi/aLiisamaximum.Itwillimportallothertradablegoodsthatit

consumes.Butweknowthatthisgivesthewageratew=Pi/aLi.Thusgiventhetechnologyofthe

nontradedgood,andspecificallyitsunitlaborrequirement,wemusthavePNT=waLNTasits

price.Notethatourassumptionsonhowspecializationintradedgoodsoccursimpliesthat

relativelysmallgesinrelativetradedpricescanleadtoacompletechangeintraded

specialization.ThisisnotsuinggiventherigidRicardiantechnicalconditionsthatwehave

specified.Whatisnoteworthyisthatthesmallshiftinpriceswillchangethewagdsothe

priceofthenontradedgood,butitwillnotleadtothesameviolentchangeinproduction.The

nontradedsectorisabletoadjustpricesandproductionlevelswithrelativelyminorfluctuations.

Thenontradedsectorcanpassontheincreasedlaborcosts,whiletheoriginaltradedsector

cannot.Notethatwecouldhavedoneanessentiallyidenticalcomparativestaticiftherewas

technicalchangeinthetradedgoods.Whatdoesthissuggestaboutthepossibleadvantagesanadvantagesofanopeneconomy?[DuetoCaves/Jones].IntraindustryTradeintheRicardianEconomy

Inrecentyears,anumberofinternationaleconomistshavemademuchofthefactthat

muchofworldtradeis“intraindustry”trade--thatis,tradeisingoodsofsimilarfactorintensity.

Aswewillseelater,theyhavearguedthatwecanaccountforsuchatradeonlyifweturnto

increasingreturnstoscaleandimperfectcompetition.However,theyignoredtheverysimplest

model--thatofRicardo.Sincethereisonlyonefactor,goodsnecessarilyhaveidenticalfactor

“intensity.”Thatis,thesimpleRicardianmodelistheparadigmaticmodelofcompetitive

intraindustrytrade.Aswewillseelater,thiscanbegeneralizedtoaworldwithmoregoodsand

factors.Theimportantpointisthatwhentherearegoodsthatareexcellentsubstitutesin

production,thentechnicaldifferencesmatter.Iftheseleadtostrongspecialization,thensimilar

countriesmayengageinintraindustry.

RicardianWorldwithInternationalLaborMobility

ItisleftambiguouswhethertheRicardiantechnologicaldifferencesaredueto

differencesinthkersthemselvesorothertechnicalconditAssumingthelatter,perfect

labormobiwillinsurethatunderitionsofcompetition,thesiteofproductionwillbe

determinedbyabsoluteadvantage.Icountryhasanabsoluteadvantageinbothgoods,the

othercountryceasestoexist.AssumeaLX<aLX*butaLY>aLY*.ThenallXisproducedathome

andallYisproducedabroad.ThenewworldPPFliesoutsidetheoldworldPPF,touchingit

onlyatthepointofinitialcompletespecialization.Theslopeis-aLX/aLY*.

RicardianProblem

T,F,oruncertain?Byopeningtotrade,weriskhavie(ormore)ofourindustrieswholly

eliminatedduetocompetition.Thisraisesgravedoubtsaboutthepossibilityofenjoyinggains

fromtrade.Surprisingly,intheRicardianworld,losinganindustryisanecessaryconditionfora

countrytoexperiencegainsfromtrade.Thereasonissimple.Itwillmaintainallindustriesonly

intheeventthattandautarkypricesareequal.Butthisisexacteconditionforenjoying

nogainsfromtrade!Hereitmaybesignificantthatweareabletoabstractfromthe

macroeconomicissuesoffullemployment,sincewewouldwanttobesurethatthereleaseof

factorsinonesectorhereallxpansioninarelativelymoreefficientsector.

RianProblem

T,F,oruncertain?InaworldRicardianeconomyinwhichtwocountriesinitiallyproducethe

samegood,onecanbecertainofcapturingtheentiremarketifitexperiencesfastertechnical

growth.SincebothprgoodX,say,wemusthavewaLX=PX=PX*=w*aLX*.Theone

thatendsupwiththelowerpricecapturetheentiremarket.Wecanseethatthisdependsnotonly

ontherateoftechnicalchange,butalsoonthegrowthrateofwagesgenerallyineachcountry.

proportionalchanges.]

IV.Thescher-Ohlin-SamuelsonModel:TheFactor

ProportionsTheory

Inthischapterwewilldevelopthefactorproportionstheoryofinternationaltrade.Ourofanalyzingtradeherewillbeeasierifwefirstreviewafewmicroeconomicprinciplesand

developasefuldiagramsthatillustratethese.

Isoquants,IsocostLinesandtheLernerDiagram

Indevelopingourintuitionregardingthedeterminantsofpatternsofinternationaltrade,it

isusefultohavesomebasicdiagramsthathelpustothinkabouttheimplicationsofchangesin

theeconomicenvironment.OnebasicbuildingblockistheLernerdiagram.Toderiveit,though,

wemustbeginbyreviewingthemeaningofanisoquant.

Itmaybeworthwhilerecallingthattheterm"iso-"meansessentially"constant."Soan

isoquantisalinealongwhichthequantityproducedisconstant.TheisoquantforagoodXis

drawnwiththeaxesgivenbythefactorinputsusedtoproducethatgood.Inourwork,wewill

havetwofactors,capindlabor,andsothesewillcorrespondtoouraxes.Ifwedrawaunit

isoquantofX,wewillshowthecombinationsofKandLthatarejustcapableofproducingone

unitofX.Notethatingeneralasweusemorelabor,wecanuselesscapital,buteachtimethat

wedothistheamountoflaborthatwehavetoaddincreasesaswehavelessandlesscapital,yet

keepproducingoneunitofX.Thisgivestheisoquantthefamiliar"bowed-in"shape,convexto

theorigin.SincetheMRTS(marginalrateoftechnicalsubstitution)istheslopeoftheisoquant,

wecanseethatthiscorrespondstodiminishingMRTSaslaborissubstitutedforcapital.[see

figure1]

GiventhataunitofoutputcouldbeproducedwithanyofthedifferentcombinationsofK

andLalongtheisoquantcurve,theproducerisfacedwiththeproblemofchoosingwhichtouse.

Theobviousansweristochoosetheonethatproducesthegivenoutputatleastcost.Fromthe

perspectiveoftheindividualproducer,thefactorpriceratio,w/r,isbeyondhercontrol.

Thus,foranygivenfactorpriceratiowecandrawalineincapital/laborspacewithslope-w/r

thatisocostline.Thatis,everycombinationofKandLonthatlinewillbesuchthat(wL+

53

rK)equalsthesameconstantnumber.[seefigure2]Obviouslylineswiththesameslopebut

furtherfromtheoriginrepresenthigherlevelsofcosts.[Bynowyoushouldseethesymmetry

betweentheseisocostlinesandtheconsumer'stypicalbudgetline,or"iso-expenditure"line.]

Thusthewaytoproduceitatleastcostistopickthepointoftangencybetweentheisoquantand

theisocostlineforthegivenw/r.Thispoftangencygivestheoptimalcapitaltolaborratio

forthegivenw/r.[seefigure3]Moreover,verysignificantlycannotethatasw/rrises(the

isocostcurvesbecomesteeper)theoptimalcapitaltolabormixwillrise.[seefigures4]This

shouldnotbesurprising--asthecostoflabor(thewage)risesrelativetocapital(therentalcost)

weshouldsubstitutetowardthefactorthathasbecomerelativelycheaper(capitalhere).This

establishesthefactthat,sayforgoodX,theoptimalkXwillbemonotonicallyincreasinginw/r.

Geometricallythiscorrespondstoasteeperlinefromtheorigintothepointoftangency.[see

figure5]Moreover,thefactthatweareworkingwithaconstantreturnstoscaleproduction

funmeansthattheoptimalcapitaltolabormixdependsonlyonthefactorpriceratio--not

onthescaleofproduction.[seeappendixonCRSproductionfunctions]

Figure5

Bylookingattheexchangemodel,wehavealreadydevelopedarelativelysophisticated

notionofdemand.Nowweneedtoaddproduction,whichitturnsoutisverysimplehere.As

pricechanges,productionmovesalongthePPF.ThuswecansummarizesupplyofXasX=

X(P).SinceP=PX/PYweeasilifythatthesupplyofXisincreasinginP.SimilarlyY=Y(P-

1

besurprising.AriseinPnecessarilymeansafallinP-1,soariseinproductionofXandafallin

production.

Wecannowinsertthisdirectlyintotheframeworkofimportdemandrtsupplythat

wedevelopedearlier--onlynowwithproductionvariable.Letuslookatthehomecountryfirst.

Whatwouldtheautarky(pre-trade)situationlooklike?Wecanseethatinthiscompetitive

economy,productionandconsumptionwouldoccuratacommonpoint,whereMRS=MRT=

PA,andwhereMRTS=w/r(sincewehavefullemploymentandareonthePPF).[seeFigure14]

Thiswouldputusattheautarkyequilibrium,pointA.Intheimportdemand/exportsupply

diagram,thisimpliesMY=0justwhenP=PA.

Wecontinuetoderivetheimportdemandschedulejustasbefore,onlweallowfor

productiontovary.Forexample,wecouldaskwhatwouldhappenifPwerePB>PA(i.e.PB-1<

PA-1).ItisclearthatproductionshiftstowardX.Consumptionmovesinthemannerdevelopedin

theearliersection.OureconomywouldimportYandexportX.

Thesamecommentsregardingtheeffectsofpricesonsupplyanddemandholdhereforthe

foreigncountry.

Balancedtradeobtainsexactlywhereourdemandforimportsequalstheirsupplyof

exports(bothofY).Noteinthederivationthatthehometdemandcutstheverticalcurveat

theautarkyprice.Correspondingly,exportsupplyisEX)−DX(P,R)=EX(P,R).

50EnglishSpanishArabic贸易平衡价格

关键是要注意的进口需求和出口供给曲线本身并不

典型给曲线。他们每个人都已经在它的整体结构

生产和需求。

实际收入，生产，弹性和贸易格局（附录）

[以下基础上的洞穴和琼斯的附录。

我们希望开始列明福利费用的来源。第一个检查显示

这些可以来约因（1）贸易条件的变化，或（2）养老变化。

有关的表达，其中RY是指在良好的Y单位的实际收入：

这一艰巨的前瞻性的表达，实际上有一些直观的内容。我们选择

衡量您的真实单位导入Ÿ良好的消费方面的福利。

不出意料的话，消费的变化，那就是福利的变化

达到-即。P级DDX+DDY（注意，价格转换成“真实”的条款，即单位X单位

Y）在这最后的表达，有两个方面。首先是“贸易条款”的影响。注意到

当p-1>0，则导入的价格已上升相对，或等价的条款

贸易恶化，我们并不感到惊讶地发现，这降低了福利。第二项是

看在我们的生产包的小变化的影响。假设我们保持充分

就业，所以留在PPF的，这些变化的一阶效应是零。原因是

我们已经在一个最佳的，因此沿PPF的捷运=DY/DX=-P。但仅仅

相乘，然后重新排列，显示P级DX+DY=0。[更先进的学生可

承认黄/的瓦伊纳信封定理的例子。贸易变化的条款，当进口的国内需求会发生什么？这是一个

复杂的问题。我们要考虑需求替代效应和收入效应，作为

以及供应任何诱导作用。我们将获得的表达反映所有这些：

我们决定对进口和出口密切相关的要求

贸易平衡。这是什么进口需求弹性的关系，并建议有关

出口供应量呢？首先让我们回顾这些条款的定义：

匀需求弹性，我们想有一个想法，贸易条件如何调整外生变化

（除了价格），在这两个国家的进口需求。我们会得到的结果是

贸易条件会变成对进口中的比例增长，具有较大的为准

需求不变的价格：

第三。李嘉图模型

在最后一章中，我们建立了一个重要的原则：如果自给自足的相对价格差异，

它有可能为国家交易的中