城市經濟學基本理論EconomicTheoriesand稀缺性，選擇和機會Scarcity,choiceandopportunity稀缺性 Resources,noma-erhowlargetheymaybe,arelimited–thisisknownasItisthescarcitythatforcesharddecisionstobemadeaboutthealloca<onof自由物品（freegoods）：選擇在有限的資howwedecidetoallocate,givenlimitedEconomicTheoriesand機機會成本OpportunityThisistherelevantcostofthedecisionbeingWheneverwechoosetohavemoreofonethingwemakesimultaneousdecisiontohavelessofsomethingItisthevalueofthenextbestalternativethatisgiven資A的機會成本，則該OCA=max(RB,RC,RD,式中：RBRCRD,……分別表示用于用途B,C,D城市經濟學基本理論與概EconomicTheoriesand價價格調整區位平Pricesadjusttoachieveloca<onal城市經濟學基本理論與概EconomicTheoriesand外部性外部性外部經濟——外部性經濟正效外部不經濟——外部性經濟負效在大多數交易中，消費者所支付的價格等于該商品的成bene?ts=然而，在某些情況下，參與交易以外的其他人將會承擔部分成這就導致了外部成本的存當存在外部成本或收益時，我們并不認為市場均衡具有社會效城市經濟學基本理論與概EconomicTheoriesand規規模Economiesof生產受規模經濟的影Produc<onissubjecttoeconomiesof當生產的平均成本下降而產出上升時，便產生了規模經濟規模經濟產生的原因有兩投入要素的不可分割性Indivisible一些資本投入存在粗放性，不能隨生產規模的縮小而減較小的廠商投入同大廠商類似規模的生產要專業化因素Factor專業化工人的工作具有連續性和熟練性，提高了生產效率城市經濟學基本理論與概EconomicTheoriesand比比較優勢原理Principleofcompara<ve解釋模布米布米每小時的6211機會成1/3kg3m1kg1m專業化導致生產的變120026321從交換中獲取的收0+1+10城市經濟學基本理論與概EconomicTheoriesand乘數Theoryofthe 卡恩（RFKahn）于乘數原理隨其試用領域不同而有投資乘數，預算乘數，對外貿易數，貨幣創造乘數等例如投資乘數 的投資變動給國民收入總量帶來的影響要比資變動本身大的多，投資的增加可能引起國民收入成倍的增城市經濟學基本理論與概EconomicTheoriesand效用U<lity效用（utility):指消費者在消費過程中獲得的一 心理滿足X為某種物品或勞務，x為該種物品或勞務的消費量，則該種物或勞務的總效用函數為無差異Indi?erence需求和需求DemandandDemand需求量(Quan%tyDemanded)：消費者在某一給定價格下希 某種商品的數量需求（Demand）：在某一特定時期內，對應于某一商品的各種價格，人們 需求和需求DemandandDemand商品的需求函數（Demand 需求曲線（DemandCurve）一種商品的需求量和他的價格之間的函數關系的圖像。需求規律（theLawofDemand）Lawofdemand‐whenthepriceofagoodrisesthentheamountofthatgoodthatisdemanded(quan%tydemanded)falls,converselywhenthepriceofagoodfalls,thentheamountofthatgooddemandedrises需求和需求DemandandDemand從個人需求到市場需求（FromindividualtomarketIndividualdemandcurvesrelate tyofagoodthatanconsumerwillpurchasetoits市場需求給定市場范圍內所有消費者對Themarketdemandcurverelatesthe tyofagoodthatallconsumersinamarketwillbuytoitsprice.需求和需求DemandandDemandDemandandDemand需求函數的需求量和需求變化Shi=sindemandcurveversuschangesinquan%ty需求量的變在其他因素保持不變的情況下，商品自身價格的變化將引起需求量的變化是由內生變量的變化引起的。表現為在一條既定的需求曲線上點的位需求的變當商品自身價格不變，由于其它因素的變化引起的需求量的變是外生變量引起的，表現為整條需求曲線的移動需求和需求DemandandDemandAdecreaseinthepriceofagoodhastwo替代效應（substitutionThesubstitutioneffectoccursbecauseconsumerstendtobuymorethegoodthathas echeaperandlessofothergoodsthathavenowerelativelymoreexpensive. e eeffectoccursbecausesinceoneofthegoodsnowcheaper,consumershaveincreasedrealpurchasing Generally,substitutionand eeffectsoccursimultaneously.影響需求的消費者的偏影響需求的消費者的偏對未來的預DemandandDemand其它商品的Twogoodsareindependentifthechangeinthepriceofonegoodhasnoe?ectonthequan<tydemandedoftheothergood.SupplyandSupplySupplySupplyandSupply供給供給——生產者在一定時期內在各種可能的價格下愿意且能夠提供的商品的數供給量——生產者在某一價格下愿意而且能夠（希望）出售的某種商品的數量個別供給——單個廠商對某種商品的供市場供給——在某個市場上所有提供相同商品的個別供給的總供給和供給SupplyandSupply一定時期內和一定市場中，某種商品的供給量和影響供給量的各個供給規律（Lawof供給和供給SupplyandSupply供給量供給量的變動(Shi=sinquan%tydemanded由商品自身價格的變化引起的供給量的變化，表現為在一條既定的供給供給的變動(Shi=sindemand當商品自身價格既定時，由于其他外生變量引起的供給量的變化，表現為影響供給的因 Equilibrium均衡Equilibrium均衡價格（Equilibrium均衡價格的變均衡Equilibrium均衡Equilibrium市場條件的變化可以導致下述四種情均衡Equilibrium均衡價消費者剩余（Consumer 生產者剩余（Producer社會生產的總剩余：消費者剩余加上生產者均衡Equilibrium最高限價總體上有利于消費者，帶來社會總剩余的減少C——社會福利的無謂損失，降低社會資源的配消費者剩余的變 生產者剩余的變 ?Cs=-費者剩余的變 ?Cs=需求彈性Anelas-citymeasuresthesensi<vityofonevariabletoMorespeci?cally,itisthepercentagechangeinonevariableresul<ngfroma1percentincreaseinanother.需求需求彈性（Elas%cityofElas-cityofdemandrelatesthepercentagechangeinquan<tydemandedtothepercentagechangeinanothervariable(priceor 需求需需求的價格彈性（Priceelas%cityof方向的，需求的價格彈性一定是負數Thepriceelas-cityofdemandmeasuresthesensi<vityofquan<tydemandedpriceMorespeci?cally,itisthepercentagechangeinquan<tydemandedofaresul<ngfroma1percentincreaseinits

Ed=

弧彈 Ed=需求富有彈性EPD<- （priceConsump<onisrela<velysensi<vetopricechangesfora1percentdecreaseinpriceyouendupwithamorethan1percentincreaseinconsump<on EPD>- (priceinelas<cConsump<onisrela<velyinsensi<vetopricechangesfora1percentdecreaseinpriceyouendupwithlessthana1percentincreaseinconsump<on需求oConsump<onandpricemovepropor<onallytoeachother1:1toWhenthepriceelas-cityofdemandisconstantallalongthedemandcurve需求完全有彈性EPD（PerfectlyPriceDemandcurvewillbePricewillbePriceelas<cityisAnyamountwillbedemandedatagivenpricebutnonewillbedemandedabovethatprice EPD=0（PerfectlyPriceInelas<c）DemandcurvewillbeQuan<tywillbeConsumersdemandthesameamountregardlessoftheprice需求需求的價格彈性和需求曲需求的價格彈性等于P/Q與需求曲線斜率的倒數的Ed= 除了完全有彈性和完全無彈性，需求的價格彈性在斜率不變的曲線上是的對于任意一條線性需求曲線上的點來說，它在需求曲線上的位置越相應的點彈性數值就越大；相反，位置越低，相應的點彈性系數值越小需求影響需求價格彈性的因——需求需求的價格彈性的大小對商品生產者總收益的設某種商品的需求函數為Qd=f(P),廠商出售這種商品的總益TR=P*Qd=P*f(P),為 P的變化對TR的影響，對TR求P的一階導 =Qd+P ]=Qd[1+Ed]需求的價格彈性的大小對消費者總支需求需求的收需求的收入彈性 eelas-cityofdemandmeasuresthesensi<vityofquan<tydemandedchanges Morespeci?cally,itisthepercentagechangeinquan<tydemandedofaresul<ngfroma1percentincrease 需求的收入彈性=需求量變化的百分比/收入變化的百分Ed’=??↑′???/??/??↑′

EY= ? ·· 需求正正常品與次Normalvs.inferior正常品（NormalNormalgoodsarethosegoodsthatconsumerswanttopurchasemoreof Apples,notebooks,次等品（inferiorInferiorgoodsarethosegoodsthatconsumerswanttopurchaserela<velylessofeincreases(i.e.,comparedtoothergoods,theywanttoconsumelessofthegood e需求需求的收入彈EID0次等品（inferiorConsump<ondecreasesas eincreasesConsump<onincreases eEID=0 eConsump<onisconstant e0<EID< e（NormalIncreaseinconsump<onis ylessthanincreaseeEID=1unit（NormalEID> eLuxuryorsuperiorIncreaseinconsump<onispropor<ona ymorethanincreasein需求需求的交叉彈性（crosselas%cityofThecross-‐priceelas-cityofdemandisthepercentagechangeinthedemandedofonegoodresul<ngfroma1percentincreaseinthepriceof需求的交叉彈性=商品??需求量變化的百分比/商品??價格變化的百分Ed’’=????↑′?????/????/????↑′SupplySupplySupply供給彈性（Supply點彈性Es=????↑′?????/????/??↑′???/?? =??/???? *???/??? 弧彈Es????↑????/(????+??↑??′)/2/??↑′SupplySupplyEs=0完全無彈性（PerfectlyInelas<c）：當價格發生變動時，供給量全沒有變化Es>1富有彈性（Elas<c）：量變化百分比大于價格變化百分Es=無窮，完全有彈性（PerfectlyElas<c）：價格任何微小的變化都以導致供給量無窮的變影響供給彈性因——生產的難易程——生產規模和規模變化的難易程——成本變需求，供給與市場Demand,Supplyand價格消費price-‐consump%onA54

D

需求曲線Demand4需求曲線Demand4EPriceE DemandGG

Food(unitsperDemand,Supplyand

收入消費收入消費D BA4 Food(unitsper4GEHGEDDD211 Food(unitsper基數效Cardinal U"lity,inaneconomiccontext,isanumericalscorewhichrepresentsthesa2sfac2onthataconsumerreceivesfromconsumingagivenmarketbasket.基數效用（Cardinal基數效用——是一種對效用的度量方法，指用基數1，2，3…….具體數量衡量效——可以具體計算并加總——邊際效用分基數效Cardinal總效用，平均效用，和邊際效總效用TUtotalu*lity——消費若干單位商品邊邊際效用MUmarginalu*lity——Cardinal總效用，平均效用，和邊基數效CardinalLawofdiminishingmarginal邊Lawofdiminishingmarginal加，從中得到的滿足程度會逐漸下降Asmoreandmoreofagoodisconsumed,consump2onofaddi2onalunitsresultsinsmallerandsmalleraddi2onstou2lity.基數效Cardinal等邊際效用Equalmarginal消費者多種商品的最大效用原則是：消費者花在每種物品上的單位貨幣支出的邊際效用（這種商品的邊際效用與其價格之比）彼此相等，都等于貨幣收Theequalmarginalprinciplestatesthatu*lity izedwhentheconsumerequalizedthemarginalu*lityperdollarofexpenditureacrossallgoodsMUx/PxMUy/Py λ邊際效用序數效序數效用Ordinal序數效用假設偏好的完備性Preferencesareassumedtocomplete.Consumerscancompareandrankpossiblebasketsintheorderthey偏好的傳遞性,偏好的一致性MoreIsBetter：consumerswillalwaysprefermoreofanygoodtoConsumersareneverMoreisalwaysbetter,evenifitisjustalittlebit序數效Indi?erence無差異Indi?erenceTheindi?erencecurveillustratescombina2onsofmarketbasketsthatprovidetheconsumerwithanequivalentlevelofsa2sfac2on序數效Food

（替代商品）無差Indi?erence Clothing等效——x,y軸分別代表兩種商品，效用面（totalu2litysurface）（constantu2litycurve），其特點——無差異曲線向右下方傾斜——無差異曲線的斜率是x,y兩種商品的邊際替代率(marginalrateof

Indi?erencecurvesfromthesamemapcannotAccordingtothisdiagram,theconsumershouldbeindi?erentamongbasketsA,BandA,D.YetBshouldbepreferredtoDbecauseBhasmoreofBOTHgoods.A Food序數效CocaCola(Cansper

互替商品的無Perfect Twogoodsareperfectsubs"tuteswhenthemarginalrateofsubs2tu2onofonefortheotherisconstant. Example:A wouldbewillingtogiveupthesameamountofCocaColatoconsumePepsi,regardlessof howmuchPepsitheyhavealreadyconsumed(Peoplenotdesireto“balance”theirconsump2onofsoda1

Pepsi(CansperLek

完全補足品PerfectTwogoodsareperfectcomplementswhenthemarginalrateofsubs2tu2oniseitherzeroorin?nite.Withperfectcomplements,addi2onalunitsofonegoodareofnovaluewithoutaddi2onalunitsoftheothergood.321

Right

序數效 中性商品無差異 肥皂序數效預算線（budget Budgetconstraintsarelimitsfacedbyconsumersbecauseof Abudgetconstraintisthesetofallbaskets(combina2onoftwoormorethatarea?ordablewitha eandgiven方程I=PxX+PyY斜率T=Y/X=(I/PC)=40

BudgetThebudgetlinerepresentsthecombina*onsofgoodsthatcanbepurchasedgiventheconsumer’s eandthepricesofthegoods.LineAG(passesthroughpointsB,D,andE)showsthebudgetassociatedwithan eof$80,apriceoffoodofPF=$1/unitandapriceofclothingofPC=$2/unit.Theslopeofthebudgetline(betweenpointsBandD)is‐PF/PC=‐10/20=‐?.

BudgetlineF+2C=Slope?C/?F=‐?=DE

80=

Food**?C/?F=‐?measurestherela*vecostoffoodandclothingi.e.becauseclothingcosts$2/unitandfoodcosts$1/unit,?unitofclothingmustbegivenuptoget1unitoffood.

80

E?ectsofchanges 4020

Achange e(withoutachangeinprices)thebudgetlinetoshiVparalleltotheoriginalbudgetline(L1).whenthe eof$80(L1)isincreasedto$160,thebudgetlineshiVsoutwardtoL2.If efallsto$40,thenthelineshiVsinwardtoL3.(I=(I=(I=

Food

商品價格變E?ectsofchangesin

Achangeinthepriceofonegood(food),withoutachangein causesthebudgetlinetorotateabouttheinterceptofthegoodthatdidnotexperienceapricechange(clothing).InthisWhenthepriceoffoodfallsfrom$1to$0.50,thebudgetlineoutwardfromL1toL2(increaseinpurchasingOntheotherhand,whenthepriceoffoodincreasesfrom$1tothebudgetlinerotatesinwardfromL1toL3(decreaseinpurchasing (PF= (PF= (PF= Food序數效消費者均——序數效用理消費 MUx/PxMUy/Py λ=邊際效用序數效收入擴展（消費）曲線 econsump*on e-‐consump"oncurverevealstheu2lity-‐ izingco ina2onsoftwogoodsasanindividualconsumer’s echanges. D BA 753

DBA44

Food(unitsper

收入消費Withallpricesofallgoods?xed,increasesin ecauseconsumerstochangetheirchoicesofmarketInthetopgraph,thebasketsthatizeu2lityforvarious (pointA‐$10,pointB‐$20,andpointD‐$30)traceoutthe consump"oncurve.EE

HDGD2DG11

Thebouomgraphillustratestherightshikofthedemandcurveinresponsetoincreasesin (PointsE,G,andHcorrespondpointsA,B,andD, Food(unitsper

e-‐consump2on upwardbecausetheconsump2onofbothfoodandclothingincreaseas(units

e-consumption

eD B

illustra2onweobserved53Priceof

A44GEHGED2

Food(unitsper

alongasingledemandcurveresponsetochangesinthepriceofagood.Withthe curve,weobserveshiksinthedemandcurve.Sinceeachdemandcurveismeasuredforapar2cularlevelofe,anychangein emustleadtoashikinthedemandcurveTheupward-‐slo consump"oncurveimpliesthatanincreasein ecausesarightshikofthedemandcurve. Food(unitsper7

eIni2allythe eisTheu2lity-‐ eisatpointA.e-consumption eincreasesto$203D observeanoutwardshikinthe3B line,allowingtheconsumerto theu2litylevelassociatedwith indi?erencecurveU2.The izingchoiceisnowatpointPriceof

GE4HGE4D2

Food(unitsper

eincreasesyetagain$30weobserveanotheroutwardshikinthebudgetline,allowingtheconsumertoauaintheu2litylevelassociatedwiththeindi?erencecurveU3.Theu2lity izingchoiceisnowatpointD. Food(unitsper序數效價格消費曲線（priceconsump*on izingcombina2onsofgoodsasthepriceofoneofthosegoods商品價格變化——預算線變化——價格消費曲線數學方程 I=序數效

Price

Ini2allythepriceoffoodis$1andu2lity izedatpointBwhichisassociatedwiththeindi?erencecurve 5444EPriceE

D

Food(unitsper

Whenthepriceoffoodincreasestothebudgetlinerotatesinwardesmoresteep–thehigherrela2vepriceoffoodcausedtheincreaseintheslopeofthebudgetline.umu2lityisnowauainedatpointAwhichisassociatedwiththeindi?erencecurveU1.Theincreasedpriceoffoodhasdecreasedtheconsumer’spurchasingpowerandin

GGH

ngsohasalsodecreasedWhenthepriceoffooddecreases,thebudgetlinerotateoutwardandtheconsumermovestoindi?erencecurveU3.Ahigherlevelofu2lityisnowachievedatpointD.

Food(unitspercurveandtheindividualdemand 54

D

價價格消費price-‐consump*on需求曲Demand4 Food需求曲Demand4EPriceE DemandGG

Food(unitsper序數效收入效應和替代效 分 力增加而增購這種商品（收入效應）在價格下降的過程中，這兩種效應是同時發生的（Generally,subs2tu2onee?ectsoccursimultaneously.）當一種商品的價格下降時，發生兩種效應（Adecreaseinthepriceofagoodtwo替代效應——效用水平保持不變時，由于商品價格的變化導致對該商品消費pauernofincreasingconsump2oninresponsetoadecreaseinpricealmostalways 價格變化的總效應——替代效應+收入效正常物劣等吉芬吉芬DosuchgoodsevenAnewstudybyRobertJensenandNolanMiller,economistsatKennedySchool,answerthis哈佛經城市經濟學基本理論EconomicTheoriesand稀缺性，選擇和機會Scarcity,choiceandopportunity稀缺性 Resources,noma-erhowlargetheymaybe,arelimited–thisisknownasItisthescarcitythatforcesharddecisionstobemadeaboutthealloca<onof自由物品（freegoods）：選擇在有限的資howwedecidetoallocate,givenlimitedEconomicTheoriesand機機會成本OpportunityThisistherelevantcostofthedecisionbeingWheneverwechoosetohavemoreofonethingwemakesimultaneousdecisiontohavelessofsomethingItisthevalueofthenextbestalternativethatisgiven資A的機會成本，則該OCA=max(RB,RC,RD,式中：RBRCRD,……分別表示用于用途B,C,D城市經濟城市經濟學基本理論EconomicTheoriesand外部性外部性外部經濟——外部性經濟正效外部不經濟——外部性經濟負效在大多數交易中，消費者所支付的價格等于該商品的成bene?ts=然而，在某些情況下，參與交易以外的其他人將會承擔部分成這就導致了外部成本的存當存在外部成本或收益時，我們并不認為市場均衡具有社會效城市經濟學基本理論與概EconomicTheoriesand效用U9lity效用（utility):指消費者在消費過程中獲得的一 心理滿足X為某種物品或勞務，x為該種物品或勞務的消費量，則該種物或勞務的總效用函數為無差異Indi?erence城市經濟城市經濟學基本理論EconomicTheoriesand消費者在消費若干數量的某種物品或勞務時，每一新增單品或勞務所帶來的總效用的變MUx=?TUx/邊際效用遞減規(Lawofdiminishingmarginal在技術不變和其它生產因素不變的前提下，連續地把同一單位的可投入量增加到一定數量的其它投入量上所引起的增量是遞減的趨勢物品價格：物品或勞務的稀缺性，即邊際效用思考：水和鉆Thetheoryofthedecisionsandhowitscostsvarywithitsoutput.Knowledgeofproduc9onandcostshelpstobuildanunderstandingofcharacteris9csofmarket成成生產會計Accoun<ngAccoun<ngcostsareactualexpenses,includinghistoricalcosts,pluschargesforcapital生產經濟成本（economicEconomiccostsarethecoststoa?rmofu<lizingeconomicresourcesinincludingopportunity——顯性成本（explicit——隱性成本（implicit生產短期成本和長期成總成本，平均成本和邊際總成本（TC）——生產某一特定數量產品所付出的成本總額TCFCTotalcostisthetotaleconomiccostofconsis<ngof?xedandvariable變動成本variablecost(VC)——隨著產量變化而變化的成本平均成本（AC）——AC=????/????????/????????/??(平均固定成本+平均變動成本化?Q=生產沉沒成本和沉沒成本SunkCosts——SunkcostsareexpendituresthathavebeenmadeandcannotbeCostCostCost短期成本平均固定成本曲線平均變動成本曲線平均成本曲線邊際成本曲成本函Cost長期平均成本（envelopcurve）長期總成本曲TheEquilibriumofthe廠商均TheEquilibriumofthe總產量，平均化廠商均TheEquilibriumofthe等產量曲線Anisoquantisashowingallpossiblecombina<onsofinputsthatyieldthesameoutput.廠商均TheEquilibriumofthe等成本 廠商均TheEquilibriumofthe廠商廠商均TheEquilibriumofthe利潤最 利潤最 ——平均收益——邊際收益利潤最 邊際收益遞減規律thelawofdiminishing在其他生產要素保持不變的條件下，如果連續的增加某種生產要素的量，那么到達某一點以后，總產量的增量是遞減TheLawofdiminishingmarginalreturnsis