清华大学中级微观经济学讲义(清华 李稻葵)31
合集下载
清华大学中级微观经济学讲义(清华 李稻葵)7
The Strong Axiom of Revealed Preference
A: ($1,$3,$10) (3,1,4). B: ($4,$3,$6) (2,5,3). C: ($1,$1,$5) (4,4,3).
Choice Prices A B C A $46 $39 $24 B $47 $41 $22 C $46 $46 $23
Digression: Science vs. Engineering (对比科学家思维与工程师思维） 找问题与解问题的不同 –要对问题提问题 要对问题提问题 务虚与务实的不同 解释世界与改造世界的不同 –旁观者与参与者的不同 旁观者与参与者的不同
Maintained Assumptions on Preferences
The Strong Axiom of Revealed Preference
Consider the following data: A: (p1,p2,p3) = (1,3,10) & (x1,x2,x3) = (3,1,4) B: (p1,p2,p3) = (4,3,6) & (x1,x2,x3) = (2,5,3) C: (p1,p2,p3) = (1,1,5) & (x1,x2,x3) = (4,4,3)
Recovering Indifference Curves
Suppose we observe: A: (p1,p2) = ($1,$1) & (x1,x2) = (15,15) B: (p1,p2) = ($2,$1) & (x1,x2) = (10,20) C: (p1,p2) = ($1,$2) & (x1,x2) = (20,10) D: (p1,p2) = ($2,$5) & (x1,x2) = (30,12) E: (p1,p2) = ($5,$2) & (x1,x2) = (12,30). Where lies the indifference curve containing the bundle A = (15,15)?
清华大学中级微观经济学讲义清华李稻葵15-文档资料26页
Marginal Revenue and Own-Price Elasticity of Demand
p
a
p (q )ab q
a/2b
a/b q
M R (q ) a 2 b q
Marginal Revenue and Own-Price p Elasticity of Demand
a
M R (q ) a 2 b q
Then Xi = (a-pi)/b and
dX
* i
1.
Therefore,
dpi b
X i * ,p i (a p p ii)/b b 1 a p ip i.
Point Own-Price Elasticity
pi
pi = a - bXi*
X j(p 1 ,p 2 ,m 1 , ,m n ) n x * ji(p 1 ,p 2 ,m i).
i 1
From Individual to Market Demand
Functions
p1
p1
p1’
p1’
p1”
p1”
p1
20
x
* 1
A
15
x
* 1
B
p1’
The “horizontal sum”
The elasticity of variable X with
respect to variable Y is
x,y
%x. %y
Slope Vs. Elasticity
Q: Why not just use the slope of a demand curve to measure the sensitivity of quantity demanded to a change in a commodity’s own price?
Ch12Uncertainty(中级微观经济学-清华大学,钟笑寒)
m L Cna Ca 1 1
slope
mL
1
Where is the most preferred state-contingent consumption plan?
m L Ca
Preferences Under Uncertainty
In
general, how a person values consumption in one state as compared to another will depend on the probability that the state in question will actually occur. Suppose that we are considering two mutually exclusive states. Let c1 and c2 represent consumption in state 1 and 2, and let 1 and 2 be the probabilities that state 1 or 2 actually occurs. Thus 1+2=1. The utility function can be written as U(c1,c2,1,2)
State-Contingent Budget Constraints
m L 1
Cna
m L Cna Ca 1 1
m
The endowment bundle.
mL
m L Ca
State-Contingent Budget Constraints
m L 1
State-Contingent Budget Constraints
《微观经济学》清华大学课件Ch5Choice消费者最优选择共37页文档
(x1*,x2*) also exhausts the budget so
p1x* 1p2x* 2m . (B)
Computing Ordinary Demands a Cobb-Douglas Example.
So we have discovered that the most preferred affordable bundle for a consumer with Cobb-Douglas preferences
x2
(x1*,x2*) is interior.
(a) (x1*,x2*) exhausts the
budget; p1x1* + p2x2* = m.
x2*
x1*
x1
Rational Constrained Choice
x2
(x1*,x2*) is interior .
(b) The slope of the indiff.
U (x1,x2)x1 axb 2
is
( ) (x * 1 ,x * 2 )(a a m b )p 1 ,(a b m b )p 2.
Computing Ordinary Demands -
a Cobb-Douglas Example.
x2
U (x1,x2)x1 axb 2
x
* 2
bm
(a b )p 2
curve at (x1*,x2*) equals the slope of the budget
constraint. x2*
x1*
x1
Rational Constrained Choice
(x1*,x2*) satisfies two conditions: (a) the budget is exhausted;
p1x* 1p2x* 2m . (B)
Computing Ordinary Demands a Cobb-Douglas Example.
So we have discovered that the most preferred affordable bundle for a consumer with Cobb-Douglas preferences
x2
(x1*,x2*) is interior.
(a) (x1*,x2*) exhausts the
budget; p1x1* + p2x2* = m.
x2*
x1*
x1
Rational Constrained Choice
x2
(x1*,x2*) is interior .
(b) The slope of the indiff.
U (x1,x2)x1 axb 2
is
( ) (x * 1 ,x * 2 )(a a m b )p 1 ,(a b m b )p 2.
Computing Ordinary Demands -
a Cobb-Douglas Example.
x2
U (x1,x2)x1 axb 2
x
* 2
bm
(a b )p 2
curve at (x1*,x2*) equals the slope of the budget
constraint. x2*
x1*
x1
Rational Constrained Choice
(x1*,x2*) satisfies two conditions: (a) the budget is exhausted;
清华大学中级微观经济学讲义(清华 李稻葵)30
The Endowment Allocation
2 OB 2 6 4 OA 6 8
ω = (2,2)
B
The Endowment Allocation
2 OB 2 6 4 OA 6 8 The endowment allocation
A ω = (6,4) B
ω = (2,2)
The Endowment Allocation
/ Remarks on the Final
Final Examination: 1. Final exam is comprehensive. 2. It mainly covers the material after midterm. 3. The materials before midterm are important in two ways: 1) some problems may directly come from those chapters. 2) the materials before midterm provide a foundation for new materials. The format of the final will be the same as that in the midterm. Office Hour: 4-5 pm Thursday
Starting an Edgeworth Box
Height = A B ω2 + ω2
= 4+ 2 =6
The dimensions of the box are the quantities available of the goods.
A B ω1 + ω1 = 6 + 2 = 8 Width =
中级微观经济学课件
况
市场均衡及其形成机制
市场均衡定义：市场上的供给和需求相等，价格不再变动的一种状态。
形成机制：在竞争市场中，价格变动会引发供给和需求的调整，最终达到市场均衡。
均衡的稳定性：在短期内，市场均衡是相对稳定的；但在长期中，市场均衡可能会因为 外部因素而发生变化。 市场均衡的意义：市场均衡是经济学的核心概念之一，对于理解市场经济运行规律和制 定经济政策具有重要的意义。
价格歧视和垄断定价
价格歧视定义：对同一商品或服务在不同市场以不同价格销售的行为。 目的：增加利润，最大化企业收益。 类型：一级、二级和三级价格歧视。 垄断定价：在独家垄断市场中，企业通过限制产量和抬高价格来最大化利润。
福利经济学及其主要观点
福利经济学定义：研究如何实现社会福利最大化的经济学分支。
消费者行为及其影响因素
消费者偏好：影响消费者行为的重要因素，决定了消费者的购买决策。 收入水平：收入水平的高低直接影响消费者的购买能力，进而影响其消费行为。 价格变动：价格变动对消费者行为有显著影响，价格上升或下降会影响消费者的需求量。 消费者预期：消费者对未来经济状况的预期会影响其当前的消费行为。
类型：垄断竞争市场、寡头市场、完全垄断市场 特点：产品差异、市场壁垒、市场集中度高、价格接受者
寡头市场的形成和竞争策略
寡头市场的定义：少数几家大企业占据了大部分的市场份额，从而影响市 场的价格和产量。
寡头市场的形成原因：市场进入壁垒、规模经济、产品差异化和政府政策 等因素导致市场结构趋于寡头化。
竞争策略：采用价格战、广告战Байду номын сангаас研发和创新等手段来争夺市场份额，提 高自身竞争力。
合作策略：通过达成协议、建立联盟等方式来共同控制市场价格和产量， 实现共赢。
市场均衡及其形成机制
市场均衡定义：市场上的供给和需求相等，价格不再变动的一种状态。
形成机制：在竞争市场中，价格变动会引发供给和需求的调整，最终达到市场均衡。
均衡的稳定性：在短期内，市场均衡是相对稳定的；但在长期中，市场均衡可能会因为 外部因素而发生变化。 市场均衡的意义：市场均衡是经济学的核心概念之一，对于理解市场经济运行规律和制 定经济政策具有重要的意义。
价格歧视和垄断定价
价格歧视定义：对同一商品或服务在不同市场以不同价格销售的行为。 目的：增加利润，最大化企业收益。 类型：一级、二级和三级价格歧视。 垄断定价：在独家垄断市场中，企业通过限制产量和抬高价格来最大化利润。
福利经济学及其主要观点
福利经济学定义：研究如何实现社会福利最大化的经济学分支。
消费者行为及其影响因素
消费者偏好：影响消费者行为的重要因素，决定了消费者的购买决策。 收入水平：收入水平的高低直接影响消费者的购买能力，进而影响其消费行为。 价格变动：价格变动对消费者行为有显著影响，价格上升或下降会影响消费者的需求量。 消费者预期：消费者对未来经济状况的预期会影响其当前的消费行为。
类型：垄断竞争市场、寡头市场、完全垄断市场 特点：产品差异、市场壁垒、市场集中度高、价格接受者
寡头市场的形成和竞争策略
寡头市场的定义：少数几家大企业占据了大部分的市场份额，从而影响市 场的价格和产量。
寡头市场的形成原因：市场进入壁垒、规模经济、产品差异化和政府政策 等因素导致市场结构趋于寡头化。
竞争策略：采用价格战、广告战Байду номын сангаас研发和创新等手段来争夺市场份额，提 高自身竞争力。
合作策略：通过达成协议、建立联盟等方式来共同控制市场价格和产量， 实现共赢。
清华大学李稻葵中级微观经济学讲义
Chapter One
The Market --- Appreciating Economic Modeling
The Purpose of this Chapter
• To begin to understand the art of building an economic model • To begin to understand three basic elements of modeling in economics:
– apartments are close or distant, but otherwise identical – distant apartments rents are exo genous (外生变量） and known – many potential renters and landlords
– Purpose – Simplification through assumptions – Value judgment
The Purpose of an Economic Model
• The purpose of an economic model is to help provide precise insights (精确的 洞察力）on a specific economic phenomenon. • Thus:
– Different phenomena needs different model; – Simplification by assumption is necessary
An Illustration: Modeling the Apartment Market
• Purpose: How are apartment rents determined? Are rents “desirable”? • Simplifying assumptions:
The Market --- Appreciating Economic Modeling
The Purpose of this Chapter
• To begin to understand the art of building an economic model • To begin to understand three basic elements of modeling in economics:
– apartments are close or distant, but otherwise identical – distant apartments rents are exo genous (外生变量） and known – many potential renters and landlords
– Purpose – Simplification through assumptions – Value judgment
The Purpose of an Economic Model
• The purpose of an economic model is to help provide precise insights (精确的 洞察力）on a specific economic phenomenon. • Thus:
– Different phenomena needs different model; – Simplification by assumption is necessary
An Illustration: Modeling the Apartment Market
• Purpose: How are apartment rents determined? Are rents “desirable”? • Simplifying assumptions:
清华大学中级微观经济学讲义
p y w 1 x 1 w 2 x ~ 2 . I.e. yw p 1x1p w 2x ~2.
.
Short-Run Iso-Profit Lines
y
Slopesw1 p
x1
.
Short-Run Profit-Maximization
y
y f(x 1 ,x ~ 2 )
.
Economic Profit
The economic profit generated by (x1,…,xm,y1,…,yn) is
p 1 y 1 p n y n w 1 x 1 w m x m .
Notes:
For the time being, we restrict to the case of a competitive firm, which is a tiny relative to the market size and takes prices p1,…,pn w1,…,wm as given constants;
.
Comparative Statics of Short-Run
Profit-Maximization
y
y f(x 1 ,x ~ 2 )
y* Slopesw1 p
x
* 1
x1
.
Comparative Statics of Short-Run
Profit-Maximization
y
equal. y*
M P1
w1 p
Slopesw1 p
a
t
(
x
* 1
,
x~
2
,
y*
)
x
* 1
x1
.
Short-Run Iso-Profit Lines
y
Slopesw1 p
x1
.
Short-Run Profit-Maximization
y
y f(x 1 ,x ~ 2 )
.
Economic Profit
The economic profit generated by (x1,…,xm,y1,…,yn) is
p 1 y 1 p n y n w 1 x 1 w m x m .
Notes:
For the time being, we restrict to the case of a competitive firm, which is a tiny relative to the market size and takes prices p1,…,pn w1,…,wm as given constants;
.
Comparative Statics of Short-Run
Profit-Maximization
y
y f(x 1 ,x ~ 2 )
y* Slopesw1 p
x
* 1
x1
.
Comparative Statics of Short-Run
Profit-Maximization
y
equal. y*
M P1
w1 p
Slopesw1 p
a
t
(
x
* 1
,
x~
2
,
y*
)
x
* 1
x1
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
Utility-Maximization
Coconuts MRS = w Budget constraint; slope = w
π*
Labor Output supply demand 0 L*
C*
Given w, RC’s quantity supplied of labor is L* and output quantity demanded is C*. 24 Labor (hours)
Production Possibilities
Coconuts
Ppf’s slope is the marginal rate of product transformation. Increasingly negative MRPT ⇒ increasing opportunity cost to specialization.
Utility-Maximization & ProfitMaximization
Profit-maximization: Coconut and labor markets both clear. – w = MPL – quantity of output supplied = C* – quantity of labor demanded = L* Utility-maximization: – w = MRS – quantity of output demanded = C* – quantity of labor supplied = L*
Coconuts MRS = MPL C* Output Labor 0 24 L* Leisure 24 0 Labor (hours) Leisure (hours) Production function
Robinson Crusoe as a Firm
Now suppose RC is both a utilitymaximizing consumer and a profitmaximizing firm. Use coconuts as the numeraire good; i.e. price of a coconut = $1. RC’s wage rate is w. Coconut output level is C.
Non-Convex Technologies
Coconuts
MRS = MPL. The Pareto optimal allocation cannot be implemented by a competitive equilibrium.
0
24
Labor (hours)
Production Possibilities
Robinson Crusoe’s Preferences
Coconuts More preferred
0
24
Leisure (hours)
Robinson Crusoe’s Preferences
Coconuts More preferred
24
0
Labor (hours)
Robinson Crusoe’s Choice
0
24
Labor (hours)
First Fundamental Theorem of Welfare Economics
A competitive market equilibrium is Pareto efficient if – consumers’ preferences are convex – there are no externalities in consumption or production.
Robinson Crusoe as a Firm
RC’s firm’s profit is π = C - wL. π = C - wL ⇔ C = π + wL, the equation of an isoprofit line. Slope = + w . Intercept = π .
Isoprofit Lines
C=π *+w . L
Utility-Maximization & ProfitMaximization
Profit-maximization: – w = MPL – quantity of output supplied = C* – quantity of labor demanded = L*
π*
0
L*
24
Labor (hours)
Pareto Efficiency
Must have MRS = MPL.
Pareto Efficiency
Coconuts MRS ≠ MP(hours)
Pareto Efficiency
Coconuts MRS ≠ MPL
Preferred consumption bundles. 0 24 Labor (hours)
Pareto Efficiency
Coconuts MRS = MPL
0
24
Labor (hours)
Pareto Efficiency
Coconuts MRS = MPL. The common slope ⇒ relative wage rate w that implements the Pareto efficient plan by decentralized pricing.
π*
C*
π*= C*−wL*
Utility-Maximization
Now consider RC as a consumer endowed with $π* who can work for $w per hour. What is RC’s most preferred consumption bundle? Budget constraint is C =π *+w . L
24
Labor (hours)
Non-Convex Technologies
Do the Welfare Theorems hold if firms have non-convex technologies? The 2nd Theorem does require that firms’ technologies be convex.
Production Possibilities
Coconuts
Production possibility frontier (ppf) Production possibility set
Fish
Production Possibilities
Coconuts
Feasible and efficient Infeasible Feasible but inefficient Fish
Coconuts Higher profit; π1 <π2 <π3
C =π + w L
π3 π2 π1
0 24
Slopes = + w
Labor (hours)
Profit-Maximization
Coconuts Isoprofit slope = production function slope i.e. w = MPL = 1× MPL = MRPL. × Production function Labor Output demand supply 0 RC gets L* 24 Given w, RC’s firm’s quantity demanded of labor is L* and output quantity supplied is C*. Labor (hours)
Resource and technological limitations restrict what an economy can produce. The set of all feasible output bundles is the economy’s production possibility set. The set’s outer boundary is the production possibility frontier.
Non-Convex Technologies
Coconuts
MRS = MPL The common slope ⇒ relative wage rate w that implements the Pareto efficient plan by decentralized pricing.
0
Non-Convex Technologies
Do the Welfare Theorems hold if firms have non-convex technologies?
Non-Convex Technologies
Do the Welfare Theorems hold if firms have non-convex technologies? The 1st Theorem does not rely upon firms’ technologies being convex.
Utility-Maximization & ProfitMaximization Coconuts
MRS = w = MPL C* Given w, RC’s quantity supplied of labor = quantity demanded of labor = L* and output quantity demanded = output quantity supplied = C*.
Second Fundamental Theorem of Welfare Economics