上财中微Chapter1

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,微观经济学,2012,教师,:,1,Instructor,陆桔利,Office:,经济学院,720,Email: juli.,Office Hours: Thursday 14:00-16:00,2,Teaching Assistant,程洪伟,Office:,经济学院,216,Email:,Office Hours: Tuesday 18:30-20:30,3,教材,“,Intermediate Microeconomics: A Modern Approach,” by Hal Varian, eighth edition, W.W.Norton & Co., 2009.,中译本,:,微观经济学：现代观点,，范里安著，费方域等译，上海三联书店，上海人民出版社，,2011.,4,参考书目,1.,曼昆，,2009,：,经济学原理：微观经济学分册,（第五版），清华大学出版社。,2.,Robert S. Pindyck, Daniel L. Rubinfeld,Microeconomics, Six Edition, Tsinghua University Press, 2005,5,成绩,课堂提问及考勤,5 %,课后作业,20%,期中考试,20%,期末考试,55%,6,Chapter One,The Market,7,Main points for chapter 1,1.1,Economic modeling,1.2. Example: Modeling the apartment market,1.2.1 Competitive market equilibrium,1.2.2 Comparative statics,1.2.3 Imperfectly Competitive Markets,a monopolistic landlord,a perfectly discriminatory monopolistic landlord,a competitive market subject to rent control.,1.2.4. Which market outcomes are desirable (,Pareto efficient)?,8,1.1. Economic Modeling,What causes what in economic systems?,Which variables are determined outside the model (,exogenous variables)?,Which variables are to be determined by the model (,endogenous variables)?,At what level of detail shall we model an economic phenomenon?,9,The Need for Abstraction,Abstraction,- ignoring many details in order to focus on the most important elements of the problem,The proper degree of abstraction depends on the objective of the analysis,10,Two Principles in Economics,Optimization,Equilibrium,11,1.2. Example: Modeling the Apartment Market,1.2.1 Competitive market equilibrium,1.2.2 Comparative statics,1.2.3 Imperfectly competitive markets,12,1.2.1 Competitive market equilibrium,Central question,: How are apartment rents determined?,Assumptions,:,apartments are close or distant, but otherwise identical,distant apartments rents are exogenous and known,many potential renters and landlords, i.e., competitive market,13,Main Questions,Who will rent close apartments?,At what price?,14,Modeling Individual Demand,Choose either distant or close apartment,Do you prefer a close apartment? Why?,When do people tend to choose a close apartment?,Decision: What is the maximum rent you are willing to pay for a close apartment?,15,Modeling Market Demand,Demand,: Suppose the most a person is willing to pay for a close apartment is $500/month. Thenp = $500,Q,D,= 1.,Suppose the price has to drop to $490 before a 2nd person would rent. Thenp = $490,Q,D,= 2.,Reservation price: maximum willingness to pay.,16,Demand curve,Demand curve,: a curve that relates the quantity demanded to price.,What is the relationship between the quantity demanded of a good and its price?,17,Market Demand Curve for close Apartments,p,Q,D,18,Modeling Apartment Supply,Supply,: It takes time to build more close apartments, therefore, the quantity available is fixed (say, at 100) in the,short-run,.,19,Market Supply Curve for Apartments,p,Q,S,100,20,Adjustment of the Market Equilibrium,If the rental price is too low (pp,e,), what happens?,21,Competitive Market Equilibrium,Quantity demanded = quantity supplied,price will neither rise nor fall,so the market is at a,competitive equilibrium,.,22,Competitive Market Equilibrium,p,Q,D,Q,S,p,e,100,People is willing to pay p,e,or more,to get close apartments.,23,Competitive Market Equilibrium,Q: Who rents the close apartments?,A: Those most willing to pay.,Q: Who rents the distant apartments?,A: Those least willing to pay.,So the competitive market allocation is by “willingness-to-pay”.,24,1.2.2 Comparative Statics (,比较静态分析,),Comparative Statics:,comparing two static equilibria to analyze how the equilibrium changes as an exogenous variable changes?,25,Exogenous variables in this model,What are the exogenous variables in this model?,price of distant apartments,quantity of close apartments,incomes of potential renters.,How the equilibrium changes if one of these exogenous variables changes?,26,The change in the price of distant apartments,Suppose distant apartments become more expensive, what happens to the market equilibrium?,Demand for close apartments?,Demand curve?,The price of the close apartments?,27,Illustration of the effect of the price change of distant apartments,p,Q,D,Q,S,p,e,100,28,The change of the quantity of close apartments,Suppose there were more close apartments, what happens to the market equilibrium?,How will the curves change?,How will the price for close departments change?,29,Illustration of the effect of the quantity change of close apartments,p,Q,D,Q,S,p,e,100,30,The change of potential renters income,Suppose potential renters income rises, what happens to the market equilibrium?,What happens to the curves? Why?,How does the price of close apartments change?,31,Illustration of the effect of income change,p,Q,D,Q,S,p,e,100,32,Taxation Policy Analysis,Local government taxes apartment owners.,What happens to,price,quantity of close apartments rented?,Is any of the tax “passed” to renters?,33,Taxation Policy Analysis,Market supply is unaffected.,Market demand is unaffected.,So the competitive market equilibrium is unaffected by the tax.,Price and the quantity of close apartments rented are not changed.,Landlords pay all of the tax.,34,1.2.3. Imperfectly Competitive Markets,We discuss 3 possibilities:,a monopolistic landlord,a perfectly discriminatory monopolistic landlord,a competitive market subject to rent control.,35,A Monopolistic Landlord,The main property of a monopoly: only one seller in the market.,Price (p) and demand D(p) are determined at the same time.,Revenue = p D(p).,How to set the price to maximize its revenue?,36,Monopolistic Market Equilibrium,p,Q,D,Q,S,Middleprice,100,Vacant close apartments.,37,Properties of a monopoly,To maximize its profit, a monopolist will restrict the output, therefore the monopoly output q,m,q,e,.,That means, the monopolist will generally charge a price that is higher than p,e,.,38,Perfectly Discriminatory Monopolistic Landlord,Imagine the monopolist knew everyones willingness-to-pay (reservation price).,Charge $500 to the most willing-to-pay,charge $490 to the 2nd most willing-to-pay, etc.,Each apartment would be rented to the person who was willing to pay the most for it.,39,Discriminatory Monopolistic Market Equilibrium,p,Q,D,Q,S,100,p,1,=$500,p,2,=$490,1,2,p,3,=$475,3,p,e,Discriminatory monopolistcharges the competitive marketprice to the last renter, andrents the competitive quantityof close apartments.,40,Rent Control,Local government imposes a maximum legal price that is lower than the competitive price, i.e. p,max, p,e,.,41,Market Equilibrium,p,Q,D,Q,S,p,e,100,p,max,Excess demand,The 100 close apartments are,no longer allocated bywillingness-to-pay (lottery, lines,large families first?).,42,1.2.4. Which market outcomes are desirable?,Four possible ways of allocating apartments:,Perfect competition,Monopoly,Discriminatory monopoly,Rent control,Which is better?,43,Pareto Efficiency,Vilfredo Pareto; 1848-1923.,A Pareto outcome allows no “wasted welfare”,Pareto Improvement,: if we can find a way to make some people better off without making anybody worse off.,Pareto efficient,: if an allocation is such that no Pareto improvements are possible.,44,Pareto Efficiency: an example,Jill has an apartment; Jack does not.,Jill values the apartment at $200; Jack would pay $400 for it.,Jill could sublet the apartment to Jack for $300.,Both gain, so it was Pareto inefficient for Jill to have the apartment.,45,Criterion for Pareto Efficiency,A Pareto inefficient outcome means there remain unrealized mutual gains-to-trade.,Any market outcome that achieves all possible gains-to-trade must be Pareto efficient.,46,Is competitive equilibrium Pareto efficient?,Competitive equilibrium:,all close apartment renters value them at the market price p,e,or more,all others value close apartments at less than p,e,so no mutually beneficial trades remain,so the outcome is Pareto efficient.,47,Pareto Efficiency,Monopoly:,not all apartments are occupied,so a distant apartment renter could be assigned a close apartment and have higher welfare without lowering anybody elses welfare.,so the monopoly outcome is Pareto inefficient.,48,Is the perfectly discriminatory monopoly Pareto efficient?,Discriminatory Monopoly:,assignment of apartments is the same as with the perfectly competitive market,so the discriminatory monopoly outcome is also Pareto efficient.,49,Pareto Efficiency,Rent Control:,some close apartments are assigned to renters valuing them at below the competitive price p,e,some renters valuing a close apartment above p,e,dont get close apartments,Pareto inefficient outcome.,50,