【正文】 a Quantity Discount m = $100 50 100 20 Slope = 2 / 1 = 2 (p1=2, p2=1) Slope = 1/ 1 = 1 (p1=1, p2=1) 80 x2 x1 121 Shapes of Budget Constraints with a Quantity Discount m = $100 50 100 20 Slope = 2 / 1 = 2 (p1=2, p2=1) Slope = 1/ 1 = 1 (p1=1, p2=1) 80 x2 x1 122 Shapes of Budget Constraints with a Quantity Discount m = $100 50 100 20 80 x2 x1 Budget Set Budget Constraint 123 Shapes of Budget Constraints with a Quantity Penalty x2 x1 Budget Set Budget Constraint 124 Shapes of Budget Constraints One Price Negative ?Commodity 1 is stinky garbage. You are paid $2 per unit to accept it。 18481923. ?A Pareto oute allows no ―wasted welfare‖。 same quantity traded. 31 Comparative Statics ?Suppose there were more close apartments. ?Supply is greater, so ?the price for close apartments falls. 32 Market Equilibrium p QD,QS pe 100 33 Market Equilibrium p QD,QS 100 Higher supply pe 34 Market Equilibrium p QD,QS pe 100 Higher supply causes a lower market price and a larger quantity traded. 35 Comparative Statics ?Suppose potential renters‘ ines rise, increasing their willingnesstopay for close apartments. ?Demand rises (upward shift), causing ?higher price for close apartments. 36 Market Equilibrium p QD,QS pe 100 37 Market Equilibrium p QD,QS pe 100 Higher ines cause higher willingnesstopay 38 Market Equilibrium p QD,QS pe 100 Higher ines cause higher willingnesstopay, higher market price, and the same quantity traded. 39 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? 40 Taxation Policy Analysis ?Market supply is unaffected. ?Market demand is unaffected. ?So the petitive market equilibrium is unaffected by the tax. ?Price and the quantity of close apartments rented are not changed. ?Landlords pay all of the tax. 41 Imperfectly Competitive Markets ?Amongst many possibilities are: –a monopolistic landlord –a perfectly discriminatory monopolistic landlord –a petitive market subject to rent control. 42 A Monopolistic Landlord ?When the landlord sets a rental price p he rents D(p) apartments. ?Revenue = pD(p). ?Revenue is low if p ? 0 ?Revenue is low if p is so high that D(p) ? 0. ?An intermediate value for p maximizes revenue. 43 Monopolistic Market Equilibrium p QD Low price Low price, high quantity demanded, low revenue. 44 Monopolistic Market Equilibrium p QD High price High price, low quantity demanded, low revenue. 45 Monopolistic Market Equilibrium p QD Middle price Middle price, medium quantity demanded, larger revenue. 46 Monopolistic Market Equilibrium p QD,QS Middle price Middle price, medium quantity demanded, larger revenue. Monopolist does not rent all the close apartments. 100 47 Monopolistic Market Equilibrium p QD,QS Middle price Middle price, medium quantity demanded, larger revenue. Monopolist does not rent all the close apartments. 100 Vacant close apartments. 48 Perfectly Discriminatory Monopolistic Landlord ?Imagine the monopolist knew everyone‘s willingnesstopay. ?Charge $500 to the most willingtopay, ?charge $490 to the 2nd most willingtopay, etc. 49 Discriminatory Monopolistic Market Equilibrium p QD,QS 100 p1 =$500 1 50 Discriminatory Monopolistic Market Equilibrium p QD,QS 100 p1 =$500 p2 =$490 1 2 51 Discriminatory Monopolistic Market Equilibrium p QD,QS 100 p1 =$500 p2 =$490 1 2 p3 =$475 3 52 Discriminatory Monopolistic Market Equilibrium p QD,QS 100 p1 =$500 p2 =$490 1 2 p3 =$475 3 53 Discriminatory Monopolistic Market Equilibrium p QD,QS 100 p1 =$500 p2 =$490 1 2 p3 =$475 3 pe Discriminatory monopolist charges the petitive market price to the last renter, and rents the petitive quantity of close apartments. 54 Rent Control ?Local government imposes a maximum legal price, pmax pe, the petitive price. 55 Market Equilibrium p QD,QS pe 100 56 Market Equilibrium p QD,QS pe 100 pmax 57 Market Equilibrium p QD,QS pe 100 pmax Excess demand 58 Market Equilibrium p QD,QS pe 100 pmax Excess demand The 100 close apartments are no longer allocated by willingnesstopay (lottery, lines, large families first?). 59 Which Market Outes Are Desirable? ?Which is better? –Rent control –Perfect petition –Monopoly –Discriminatory monopoly 60 Pareto Efficiency ?Vilfredo Pareto。 slope flattens from p1‘/p2 to p1‖/p2 p1‘/p2 p1‖/p2 96 97 Relative Prices（計價物） ?The budget line p1x1 + p2x2 = m ?Can be equivalently expressed as ? p1/p2 x1 + x2 = m/p2 ?p2=1: numeraire price(基準價格 ), it defines all prices relative to p2． ?x2 is posite good, which is measured in dollars to be spent on goods other than good 1. 98 政府政策如何影響消費者預算約束？ 99 Uniform Ad Valorem Sales Taxes ?An ad valorem sales tax levied at a rate of t ?increases all prices by tp from p to (1+t)p. 100 Uniform Ad Valorem Sales Taxes ?A uniform sales tax levied at rate t changes the constraint from p1x1 + p2x2 = m to (1+t)p1x1 + (1+t)p2x2 = m 101 Uniform Ad Valorem Sales Taxes ?A uniform sales tax levied at rate t changes the constraint from p1x1 + p2x2 = m to (1+t)p1x1 + (1+t)p2x2 = m . p1x1 + p2x2 = m/(1+t). 102 Uniform Ad Valorem Sales Taxes x2 x1 mp2mp1p1x1 + p2x2 = m 103 Unif