国际贸易理论与政策

Uw Ue Ua
O
X
Chapter 2 Technology and Trade： the Ricardian Model
The role of technology in explaining trade patterns is focus of this chapter. The earliest model of trade, that
(d) Technologies differ between the two countries.
Solving Equilibrium
II. Production Possibility Frontier
aLX labor required to produce one unit of X aLY labor required to produce one unit of Y
L a LY
O
L
X
aLX
The Pre-trade Economy
III. Autarky Equilibrium
Profit Maximization:
wx pX aLX wy pY aLY
pa
pX pY
aLX aLY
Demand has no role in determining pre-trade prices.
The Pre-trade Economy
Y
L a LY
O
L
X
aLX
The Pre-trade Economy
III. Comparative Advantage
Assume that Home has a relative higher productivity in X:
aLX aLY
aLX aLY
The International Exchange and The Gains from Trade
I. The Causes of International Trade
1. General Equilibrium in the Closed Economy
The International Exchange and The Gains from Trade
a1 a1*
a2 a2*
an an*
The Extension of the Ricardian Model
w w*
ai ,
ai*
i 1,, k
aj a*j
,
j k 1,, n
VII. An Application of Ricadian Model： Trade and Wage Inequality
w pWX , aLX
w*
pYW aL*Y
w pWX
1 aLX
w* pYW
1 aL*Y
The Welfare of Free Trade
Changes in Real Wages (from Autarky to free trade）
In terms of
X
Y
Home
w1 pWX , aLX
no change
w pWX aL*Y TOT Relative_ Productivity
w*
pYW aLX
The Extension of the Ricardian Model
VI. The Ricardian Model with Many Goods
a1, a2, , an
a1*, a2*, , an*
1. The Gains-from-Trade Theorem
If the value of free trade consumption at free trade prices exceeds the value of autarky consumption at free trade prices, then the free trade consumption bundle must be preferred to the autarky bundle, because if it were not, consumers would pick the cheaper autarky.
II. Gains from Trade
Y
O
X
A country to trade at any price ratio other than its
autarky prices must make the country better off.
The International Exchange and The Gains from Trade
Full employment condition:
aLX X aLY Y L
Production Possibility Frontier (PPF)
Y The slope of the PPF, aLX corresponds to a LY
the opportunity cost of production in the economy.
Y
pw
pX pY
pw
p*X pY*
Y
O
The Home country
pw
XO
X
The Foreign Country
The Welfare of Free Trade
V. The Gains from Trade and the Role of Wages
1. Real wage in free trade
pxw
X
w c
pywYcw
pxw Xc
pywYc
The International Exchange and The Gains from Trade
Y E
Q
pw
O
X
The International Exchange and The Gains from Trade
2. Decomposition of Trade Gains Y
The Heckscher-Ohlin-Samuelson Model
I. The Two-Factor, Two-Sector Framework: The Basic Model
This framework has the following key assumptions: (a) Each economy is endowed with fixed amounts of two homogenous factors, labor and capital, denoted by L and K respectively. (b) Two sectors produce two homogenous goods, labeled good 1 and 2. The production function of sector i, i=1, 2, is linearly homogenous. In other words, production technology is constant return to scale.
pa
pX pY
aLX aLY
aL*X aL*Y
p*X pY*
pa*
So Home has a comparative advantage in good X
The Pre-trade Economy
Y
L* aL*Y
L a LY
Foreign
Home
O
L*
L
X
aL*X
aLX
IV. Free-Trade Equilibrium
The Ricardian Model
I. The Basic Framework
In the Ricardian model, there are two sectors (X, Y) and one homogeneous factor, labor, on several assumptions as follows:
(a) Labor is the only factor used in production of X and Y;
(b) Labor is perfectly mobile within each country but internationally immobile;
(c) Labor input required per unit of output remain constant;
Foreign
w* pWX
pYW pWX
/ aL*Y
aL*Y aL*X
/ aL*Y
1 aL*X,
rise
w pYW
pWX pYW
/ aLX
aLX aLY
/ aLX
1 aLY
rise
w* 1 pYW aL*Y
no change
Labor Productivity and Wages
2. International wage comparisons and productivities
Chapter 2 The Heckscher-OhlinSamuelson Model
In this chapter we analyze the effects of international difference in factor endowments on trade and welfare by presenting the famous the Heckscher-OhlinSamuelson model, which was named for thห้องสมุดไป่ตู้ two Swedish economists who developed its essentials, and Samuelson who formalised the original model. The model departs from the Ricardian model in two fundamental ways: (1) introduction of second factor, (2) different factor abundance rather than different technologies between two nations. Three important results are demonstrated in the chapter: the H-O theorem, the Stolper-Samuelson theorem, and the Rybczynski theorem.
associated with the name of David Ricardo, is used to
discuss this. It is assumed that labor is the only factor of production in the model. By difference in technology, we mean that labor productivities differ across countries. International trade occurs based on the difference in labor productivities among countries.
Y
Autarky equilibrium conditions:
pa
px py
MRT
E
Ua
pa
px py
MRS
p
O
Xc X p
X
Yc Yp
The International Exchange and The Gains from Trade
2. General Equilibrium in the Open Economy
International Trade: Theory and Policy
Chapter 1 International Exchange and Gains from Trade
This chapter establishes a fundamental result:
If relative prices differ between countries in the absence of trade, both (all) countries can gain by exchanging commodities at any intermediate price ratio.
Y C
D O
Q p X
The International Exchange and The Gains from Trade
Trading equilibrium conditions:
pw
p
w x
p
w y
MRT
pw
p
w x
p
w y
MRS
p
w x
(
X
p
Xc)
p
w y
(Yc
Yp )
The International Exchange and The Gains from Trade