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International Economics Lecture 3: The Heckscher-Ohlin Model Min Hua & Yiqing Xie School of Economics Fudan University Mar. 19, 2014 Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 1 / 33

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  • International EconomicsLecture 3: The Heckscher-Ohlin Model

    Min Hua & Yiqing Xie

    School of EconomicsFudan University

    Mar. 19, 2014

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 1 / 33

  • Outline

    Heckscher-Ohlin Model: an Intuitive Approach

    Heckscher-Ohlin Theorem: a Formal Approach

    Factor-Price-Equalization Theorem

    Rybczynski Theorem

    Stolper-Samuelson Theorem

    Summary

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 2 / 33

  • Heckscher-Ohlin Model: Model Assumptions

    Two Goods: X1 and X2

    Two Factors: V1 and V2, Vij is industry i’s use of factor j

    X1 = F1(V11, V12) X2 = F2(V21, V22)

    V 1 = V11 + V21 V 2 = V12 + V22 (1)

    Two countries: h and f

    V11V12

    >V21V22

    andV h1

    V h2>V f1

    V f2(2)

    Identical Technologies

    CRS and Perfect Competition

    Identical Homogeneous Demand

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 3 / 33

  • Heckscher-Ohlin ModelFactor Intensities and Factor Abundance

    Factor Intensities – Characteristics of technologies

    Definition of factor intensities:

    If at a given factor-price ratio w1/w2,

    optimal factor input ratios are V11V12 >V21V22

    X1 is said to be V1 intensive and X2 is V2 intensive.

    Factor Abundance – Characteristics of countries

    Let V kj give country k’s endowment of factor j.

    Then if V h1V h2

    >V f1V f2

    country h is said to be V1 abundant, f is V2 abundant.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 4 / 33

  • Heckscher-Ohlin ModelFactor Intensities and Factor Abundance

    Factor Intensities – Characteristics of technologies

    Definition of factor intensities:

    If at a given factor-price ratio w1/w2,

    optimal factor input ratios are V11V12 >V21V22

    X1 is said to be V1 intensive and X2 is V2 intensive.

    Factor Abundance – Characteristics of countries

    Let V kj give country k’s endowment of factor j.

    Then if V h1V h2

    >V f1V f2

    country h is said to be V1 abundant, f is V2 abundant.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 4 / 33

  • Heckscher-Ohlin Model: DataFactor Intensities

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 5 / 33

  • Heckscher-Ohlin Model: DataRelative Factor Endowments

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 6 / 33

  • Heckscher-Ohlin Model: DataWorld Factor Endowments

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 7 / 33

  • Heckscher-Ohlin Model: TheoremEach country will export the good using intensively its abundant factor.

    Step 1: Comparative advantage is indirect.

    Differences in relative endowments between countries+

    Differences in relative factor intensities between goods=

    Comparative advantage

    Step 2: Autarky prices reflect comparative advantage.

    Each country has a relatively low price for the good usingintensively its abundant factor.

    Step 3: Free trade prices must lie between the two autarky prices.

    In free trade, each country exports the good using intensively itsabundant factor.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 8 / 33

  • Heckscher-Ohlin Model: TheoremEach country will export the good using intensively its abundant factor.

    Step 1: Comparative advantage is indirect.

    Differences in relative endowments between countries+

    Differences in relative factor intensities between goods=

    Comparative advantage

    Step 2: Autarky prices reflect comparative advantage.

    Each country has a relatively low price for the good usingintensively its abundant factor.

    Step 3: Free trade prices must lie between the two autarky prices.

    In free trade, each country exports the good using intensively itsabundant factor.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 8 / 33

  • Heckscher-Ohlin Model: TheoremEach country will export the good using intensively its abundant factor.

    Step 1: Comparative advantage is indirect.

    Differences in relative endowments between countries+

    Differences in relative factor intensities between goods=

    Comparative advantage

    Step 2: Autarky prices reflect comparative advantage.

    Each country has a relatively low price for the good usingintensively its abundant factor.

    Step 3: Free trade prices must lie between the two autarky prices.

    In free trade, each country exports the good using intensively itsabundant factor.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 8 / 33

  • Heckscher-Ohlin Model: A Special Case

    Figure 8.1

    Figure 8.2

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 9 / 33

  • Heckscher-Ohlin Model: A Special Case

    Figure 8.1 Figure 8.2

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 9 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit ConditionConsider a single country,[

    c1(w1, w2)c2(w1, w2)

    ]=

    [a11 a12a21 a22

    ] [w1w2

    ]=

    [p1p2

    ](3)

    ci: the production cost pi: the good price wj : the factor price

    aij : the optimal amount of factor j used in industry i

    c1 = a11w1 + a12w2 = p1

    c2 = a21w1 + a22w2 = p2

    dc1 = a11dw1 + a12dw2 + [w1da11 + w2da12] = dp1 (4)dc2 = a21dw1 + a22dw2 + [w1da21 + w2da22] = dp2

    The term in brackets is ZERO:

    aij is optimally chosen, small changes in these values have no effect incost.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 10 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit ConditionConsider a single country,[

    c1(w1, w2)c2(w1, w2)

    ]=

    [a11 a12a21 a22

    ] [w1w2

    ]=

    [p1p2

    ](3)

    ci: the production cost pi: the good price wj : the factor price

    aij : the optimal amount of factor j used in industry i

    c1 = a11w1 + a12w2 = p1

    c2 = a21w1 + a22w2 = p2

    dc1 = a11dw1 + a12dw2 + [w1da11 + w2da12] = dp1 (4)dc2 = a21dw1 + a22dw2 + [w1da21 + w2da22] = dp2

    The term in brackets is ZERO:

    aij is optimally chosen, small changes in these values have no effect incost.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 10 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit ConditionConsider a single country,[

    c1(w1, w2)c2(w1, w2)

    ]=

    [a11 a12a21 a22

    ] [w1w2

    ]=

    [p1p2

    ](3)

    ci: the production cost pi: the good price wj : the factor price

    aij : the optimal amount of factor j used in industry i

    c1 = a11w1 + a12w2 = p1

    c2 = a21w1 + a22w2 = p2

    dc1 = a11dw1 + a12dw2 + [w1da11 + w2da12] = dp1 (4)dc2 = a21dw1 + a22dw2 + [w1da21 + w2da22] = dp2

    The term in brackets is ZERO:

    aij is optimally chosen, small changes in these values have no effect incost.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 10 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit Condition[

    dc1dc2

    ]=

    [a11 a12a21 a22

    ] [dw1dw2

    ]=

    [dp1dp2

    ](5)

    By Cramer’s Rule,[a22/D −a12/D−a21/D a11/D

    ] [dp1dp2

    ]=

    [dw1dw2

    ](6)

    Since X1 is V1 intensive, so that

    a11a12

    >a21a22

    a11a22 > a12a21 a11a22 − a12a21 ≡ D > 0 (7)

    Let p2 = 1 and dp2 = 0,[dw1dp1

    ]dp2=0

    > 0

    [dw2dp1

    ]dp2=0

    < 0 (8)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 11 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit Condition[

    dc1dc2

    ]=

    [a11 a12a21 a22

    ] [dw1dw2

    ]=

    [dp1dp2

    ](5)

    By Cramer’s Rule,[a22/D −a12/D−a21/D a11/D

    ] [dp1dp2

    ]=

    [dw1dw2

    ](6)

    Since X1 is V1 intensive, so that

    a11a12

    >a21a22

    a11a22 > a12a21 a11a22 − a12a21 ≡ D > 0 (7)

    Let p2 = 1 and dp2 = 0,[dw1dp1

    ]dp2=0

    > 0

    [dw2dp1

    ]dp2=0

    < 0 (8)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 11 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit Condition[

    dc1dc2

    ]=

    [a11 a12a21 a22

    ] [dw1dw2

    ]=

    [dp1dp2

    ](5)

    By Cramer’s Rule,[a22/D −a12/D−a21/D a11/D

    ] [dp1dp2

    ]=

    [dw1dw2

    ](6)

    Since X1 is V1 intensive, so that

    a11a12

    >a21a22

    a11a22 > a12a21 a11a22 − a12a21 ≡ D > 0 (7)

    Let p2 = 1 and dp2 = 0,[dw1dp1

    ]dp2=0

    > 0

    [dw2dp1

    ]dp2=0

    < 0 (8)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 11 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit Condition[

    dc1dc2

    ]=

    [a11 a12a21 a22

    ] [dw1dw2

    ]=

    [dp1dp2

    ](5)

    By Cramer’s Rule,[a22/D −a12/D−a21/D a11/D

    ] [dp1dp2

    ]=

    [dw1dw2

    ](6)

    Since X1 is V1 intensive, so that

    a11a12

    >a21a22

    a11a22 > a12a21 a11a22 − a12a21 ≡ D > 0 (7)

    Let p2 = 1 and dp2 = 0,[dw1dp1

    ]dp2=0

    > 0

    [dw2dp1

    ]dp2=0

    < 0 (8)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 11 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit Condition

    Increase in p1 ⇒ Increase in w1 and decrease in w2

    Increase in w1 and decrease in w2⇒ Increase in a12, a22 and decrease in a11, a21

    da11dp1

    < 0da12dp1

    > 0da21dp1

    < 0da22dp1

    > 0 (9)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 12 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit Condition

    Increase in p1 ⇒ Increase in w1 and decrease in w2

    Increase in w1 and decrease in w2⇒ Increase in a12, a22 and decrease in a11, a21

    da11dp1

    < 0da12dp1

    > 0da21dp1

    < 0da22dp1

    > 0 (9)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 12 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachZero Profit Condition

    Increase in p1 ⇒ Increase in w1 and decrease in w2

    Increase in w1 and decrease in w2⇒ Increase in a12, a22 and decrease in a11, a21

    da11dp1

    < 0da12dp1

    > 0da21dp1

    < 0da22dp1

    > 0 (9)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 12 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachFactor Market Clearing Condition

    [a11 a21a12 a22

    ] [X1X2

    ]=

    [V1V2

    ](10)

    Apply Eq. (7), [a22/D −a21/D−a12/D a11/D

    ] [V1V2

    ]=

    [X1X2

    ](11)

    Divide the first equation by the second in (11),

    X1X2

    =a22 − a21 V2V1−a12 + a11 V2V1

    (12)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 13 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachFactor Market Clearing Condition

    [a11 a21a12 a22

    ] [X1X2

    ]=

    [V1V2

    ](10)

    Apply Eq. (7), [a22/D −a21/D−a12/D a11/D

    ] [V1V2

    ]=

    [X1X2

    ](11)

    Divide the first equation by the second in (11),

    X1X2

    =a22 − a21 V2V1−a12 + a11 V2V1

    (12)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 13 / 33

  • Heckscher-Ohlin Theorem: a Formal ApproachFactor Market Clearing Condition

    [a11 a21a12 a22

    ] [X1X2

    ]=

    [V1V2

    ](10)

    Apply Eq. (7), [a22/D −a21/D−a12/D a11/D

    ] [V1V2

    ]=

    [X1X2

    ](11)

    Divide the first equation by the second in (11),

    X1X2

    =a22 − a21 V2V1−a12 + a11 V2V1

    (12)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 13 / 33

  • Heckscher-Ohlin Theorem: a Formal Approach

    da11dp1

    < 0da12dp1

    > 0da21dp1

    < 0da22dp1

    > 0 (9)

    X1X2

    =a22 − a21 V2V1−a12 + a11 V2V1

    (12)

    The production ratio X1/X2 rises with p1/p2.

    The relative supply of good X1 rises with the relative price of X1.

    The price ratio (p1/p2) at which a country just begins to produceX1 is higher in the V2 abundant country.

    The price ratio (p1/p2) at which a country stops producing X2 ishigher in the V2 abundant country.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 14 / 33

  • Heckscher-Ohlin Theorem: a Formal Approach

    da11dp1

    < 0da12dp1

    > 0da21dp1

    < 0da22dp1

    > 0 (9)

    X1X2

    =a22 − a21 V2V1−a12 + a11 V2V1

    (12)

    The production ratio X1/X2 rises with p1/p2.

    The relative supply of good X1 rises with the relative price of X1.

    The price ratio (p1/p2) at which a country just begins to produceX1 is higher in the V2 abundant country.

    The price ratio (p1/p2) at which a country stops producing X2 ishigher in the V2 abundant country.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 14 / 33

  • Heckscher-Ohlin Theorem: a Formal Approach

    da11dp1

    < 0da12dp1

    > 0da21dp1

    < 0da22dp1

    > 0 (9)

    X1X2

    =a22 − a21 V2V1−a12 + a11 V2V1

    (12)

    The production ratio X1/X2 rises with p1/p2.

    The relative supply of good X1 rises with the relative price of X1.

    The price ratio (p1/p2) at which a country just begins to produceX1 is higher in the V2 abundant country.

    The price ratio (p1/p2) at which a country stops producing X2 ishigher in the V2 abundant country.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 14 / 33

  • Heckscher-Ohlin Theorem: a Formal Approach

    da11dp1

    < 0da12dp1

    > 0da21dp1

    < 0da22dp1

    > 0 (9)

    X1X2

    =a22 − a21 V2V1−a12 + a11 V2V1

    (12)

    The production ratio X1/X2 rises with p1/p2.

    The relative supply of good X1 rises with the relative price of X1.

    The price ratio (p1/p2) at which a country just begins to produceX1 is higher in the V2 abundant country.

    The price ratio (p1/p2) at which a country stops producing X2 ishigher in the V2 abundant country.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 14 / 33

  • Heckscher-Ohlin Model: A Formal ApproachRecall that country h is V1 abundant and country f is V2 abundant.

    Figure 8.3

    Figure 8.4

    Each country will export the good using intensively its abundant factor.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 15 / 33

  • Heckscher-Ohlin Model: A Formal ApproachRecall that country h is V1 abundant and country f is V2 abundant.

    Figure 8.3 Figure 8.4

    Each country will export the good using intensively its abundant factor.Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 15 / 33

  • Heckscher-Ohlin Model: A Formal ApproachIncome Distribution Effect of Trade

    Autarky: the scarcity of one factor make the good using that factorintensively expensive.

    Trade makes that good cheaper, leads the country to produce lessof that good and more of the good which does not use that factorintensively.

    This is going to lower the demand for the scarce factor, and thiswill drive down its price in equilibrium.

    The reverse argument can be made about the abundant factor.

    Trade increases the return to the abundant factor, lowers the return tothe scarce factor.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 16 / 33

  • Heckscher-Ohlin Model: A Formal ApproachIncome Distribution Effect of Trade

    Autarky: the scarcity of one factor make the good using that factorintensively expensive.

    Trade makes that good cheaper, leads the country to produce lessof that good and more of the good which does not use that factorintensively.

    This is going to lower the demand for the scarce factor, and thiswill drive down its price in equilibrium.

    The reverse argument can be made about the abundant factor.

    Trade increases the return to the abundant factor, lowers the return tothe scarce factor.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 16 / 33

  • Factor-Price-Equalization Theorem (FPE)

    Assumptions:

    Both countries have identical CRS technologies.

    Trade is completely costless so that goods price are equalized.

    Both countries produce both goods in free-trade equilibrium.

    The Factor-Price-Equalization Theorem

    (A) if trade is costless such that trade equalizes commodity pricesbetween countries and

    (B) if countries are not “too different" such that both continue toproduce both goods after trade,

    then the price of each factor is equalized across countries.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 17 / 33

  • Factor-Price-Equalization Theorem (FPE)

    Assumptions:

    Both countries have identical CRS technologies.

    Trade is completely costless so that goods price are equalized.

    Both countries produce both goods in free-trade equilibrium.

    The Factor-Price-Equalization Theorem

    (A) if trade is costless such that trade equalizes commodity pricesbetween countries and

    (B) if countries are not “too different" such that both continue toproduce both goods after trade,

    then the price of each factor is equalized across countries.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 17 / 33

  • Factor-Price-Equalization Theorem (FPE)Unit Value Isoquant and Unit Value Isocost

    For both countries,

    a22a21

    >V 2

    V 1>a12a11

    Identical technologies,equalized commodity prices⇒ Same unit-value isoquants

    Same unit value isoquants⇒ Same isocost line⇒ FPE

    Endowment point at E1 or E2

    Figure 8.5

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 18 / 33

  • Factor-Price-Equalization Theorem (FPE)World Edgewood Box

    Figure 8.6

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 19 / 33

  • Rybczynski Theorem

    Assumptions and Intuition

    Start from FPE, subject to producing both goods:

    Hold commodity prices constant⇒Hold factor prices constant⇒Hold optimal aij ’s constant⇒Changes in endowments can be absorbed through changes in thecomposition of output rather than changes in factor prices.

    The Rybczynski Theorem

    Holding commodity prices constant, an increase in theendowment of factor j leads to a more than proportion increase inthe output of the good using that factor intensively, and to a fall inthe output of the other good.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 20 / 33

  • Rybczynski Theorem

    Assumptions and Intuition

    Start from FPE, subject to producing both goods:

    Hold commodity prices constant⇒Hold factor prices constant⇒Hold optimal aij ’s constant⇒Changes in endowments can be absorbed through changes in thecomposition of output rather than changes in factor prices.

    The Rybczynski Theorem

    Holding commodity prices constant, an increase in theendowment of factor j leads to a more than proportion increase inthe output of the good using that factor intensively, and to a fall inthe output of the other good.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 20 / 33

  • Rybczynski Theorem: Graphical Presentation

    Figure 8.7

    Figure 8.8

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 21 / 33

  • Rybczynski Theorem: Graphical Presentation

    Figure 8.7 Figure 8.8

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 21 / 33

  • Rybczynski Theorem: Formal Proof[a11 a21a12 a22

    ] [X1X2

    ]=

    [V1V2

    ](10)

    Total derivative of (10):

    a11dX1 + a21dX2 = dV1 =

    [V11X1

    ]dX1 +

    [V21X2

    ]dX2

    a12dX1 + a22dX2 = dV2 =

    [V12X1

    ]dX1 +

    [V22X2

    ]dX2 (13)

    Dividing the total factor endowments V1 and V2,[V11V1

    ]dX1X1

    +

    [V21V1

    ]dX2X2

    =dV1V1

    (14)[V12V2

    ]dX1X1

    +

    [V22V2

    ]dX2X2

    =dV2V2

    (15)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 22 / 33

  • Rybczynski Theorem: Formal Proof[a11 a21a12 a22

    ] [X1X2

    ]=

    [V1V2

    ](10)

    Total derivative of (10):

    a11dX1 + a21dX2 = dV1 =

    [V11X1

    ]dX1 +

    [V21X2

    ]dX2

    a12dX1 + a22dX2 = dV2 =

    [V12X1

    ]dX1 +

    [V22X2

    ]dX2 (13)

    Dividing the total factor endowments V1 and V2,[V11V1

    ]dX1X1

    +

    [V21V1

    ]dX2X2

    =dV1V1

    (14)[V12V2

    ]dX1X1

    +

    [V22V2

    ]dX2X2

    =dV2V2

    (15)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 22 / 33

  • Rybczynski Theorem: Formal Proof[a11 a21a12 a22

    ] [X1X2

    ]=

    [V1V2

    ](10)

    Total derivative of (10):

    a11dX1 + a21dX2 = dV1 =

    [V11X1

    ]dX1 +

    [V21X2

    ]dX2

    a12dX1 + a22dX2 = dV2 =

    [V12X1

    ]dX1 +

    [V22X2

    ]dX2 (13)

    Dividing the total factor endowments V1 and V2,[V11V1

    ]dX1X1

    +

    [V21V1

    ]dX2X2

    =dV1V1

    (14)[V12V2

    ]dX1X1

    +

    [V22V2

    ]dX2X2

    =dV2V2

    (15)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 22 / 33

  • Rybczynski Theorem: Formal Proof

    The share of factor j used in good i – λij

    Proportional change in a variable – ˆ[λ11 λ21λ12 λ22

    ] [X̂1X̂2

    ]=

    [V̂1V̂2

    ](16)

    Invert the equation system,[λ22/Dλ −λ21/Dλ−λ12/Dλ λ11/Dλ

    ] [V̂1V̂2

    ]=

    [X̂1X̂2

    ](17)

    Dλ ≡ λ11λ22−λ12λ21 > 0 whereλ22

    λ11λ22 − λ12λ21> 1 given 0 < λij < 1

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 23 / 33

  • Rybczynski Theorem: Formal Proof

    The share of factor j used in good i – λij

    Proportional change in a variable – ˆ[λ11 λ21λ12 λ22

    ] [X̂1X̂2

    ]=

    [V̂1V̂2

    ](16)

    Invert the equation system,[λ22/Dλ −λ21/Dλ−λ12/Dλ λ11/Dλ

    ] [V̂1V̂2

    ]=

    [X̂1X̂2

    ](17)

    Dλ ≡ λ11λ22−λ12λ21 > 0 whereλ22

    λ11λ22 − λ12λ21> 1 given 0 < λij < 1

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 23 / 33

  • Rybczynski Theorem: Formal ProofThe magnitudes and signs of the mapping in (17) are as follows.[

    > 1 < 0< 0 > 1

    ] [V̂1V̂2

    ]=

    [X̂1X̂2

    ](18)

    Given V̂1 > 0 and V̂2 = 0 or V̂1 = 0 and V̂2 > 0,

    The Rybczynski theorem (“Magnification" effect):

    X̂1 > V̂1 > V̂2 = 0 > X̂2 X̂2 > V̂2 > V̂1 = 0 > X̂1 (19)

    Small open economyEast and South-East Asia Development

    High saving and investment rates (falling birth rates)

    ⇒ Increase in the relative capital abundance⇒ Sectoral shifts toward manufacturing

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 24 / 33

  • Rybczynski Theorem: Formal ProofThe magnitudes and signs of the mapping in (17) are as follows.[

    > 1 < 0< 0 > 1

    ] [V̂1V̂2

    ]=

    [X̂1X̂2

    ](18)

    Given V̂1 > 0 and V̂2 = 0 or V̂1 = 0 and V̂2 > 0,

    The Rybczynski theorem (“Magnification" effect):

    X̂1 > V̂1 > V̂2 = 0 > X̂2 X̂2 > V̂2 > V̂1 = 0 > X̂1 (19)

    Small open economyEast and South-East Asia Development

    High saving and investment rates (falling birth rates)

    ⇒ Increase in the relative capital abundance⇒ Sectoral shifts toward manufacturing

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 24 / 33

  • Rybczynski Theorem: Formal ProofThe magnitudes and signs of the mapping in (17) are as follows.[

    > 1 < 0< 0 > 1

    ] [V̂1V̂2

    ]=

    [X̂1X̂2

    ](18)

    Given V̂1 > 0 and V̂2 = 0 or V̂1 = 0 and V̂2 > 0,

    The Rybczynski theorem (“Magnification" effect):

    X̂1 > V̂1 > V̂2 = 0 > X̂2 X̂2 > V̂2 > V̂1 = 0 > X̂1 (19)

    Small open economyEast and South-East Asia Development

    High saving and investment rates (falling birth rates)

    ⇒ Increase in the relative capital abundance⇒ Sectoral shifts toward manufacturing

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 24 / 33

  • Stolper-Samuelson Theorem: Intuition

    Note that the opening of trade shift production in each countrytoward the sector which uses intensively the country’s abundantfactor.

    The problem is that, at constant factor prices, the expandingsector is going to demand factors in different proportions to thosebeing released by the contracting sector.

    Relative to the contracting sector, the expanding sector willdemand “too much" of the abundant factor and “too little" of thescarce factor.

    Constant factor prices will NOT lead to an open to trade equilibrium.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 25 / 33

  • Stolper-Samuelson Theorem: Intuition

    At constant factor prices,

    X2 releases factors in the proportion a22/a21.

    X1 demands factors in the proportion a12/a11.

    a22/a21 > a12/a11

    Price changes due to the opening of trade

    ⇒ Changes in outputs⇒ Excess demand for the abundant factor

    Excess supply of the scarce factor

    ⇒ Increased price of the abundant factorDecreased price for the scarce factor

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 26 / 33

  • Stolper-Samuelson Theorem: Intuition

    At constant factor prices,

    X2 releases factors in the proportion a22/a21.

    X1 demands factors in the proportion a12/a11.

    a22/a21 > a12/a11

    Price changes due to the opening of trade

    ⇒ Changes in outputs⇒ Excess demand for the abundant factor

    Excess supply of the scarce factor

    ⇒ Increased price of the abundant factorDecreased price for the scarce factor

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 26 / 33

  • Stolper-Samuelson Theorem: Graphical Presentation

    Figure 8.9

    Figure 8.10

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 27 / 33

  • Stolper-Samuelson Theorem: Graphical Presentation

    Figure 8.9 Figure 8.10

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 27 / 33

  • Stolper-Samuelson Theorem: The Theorem

    Stolper-Samuelson Theorem:

    Holding factor endowments constant, an increase in the price of one

    good leads to a more than proportional increase in the price of the

    factor used intensively in producing that good, and to a fall in the price

    of the other factor.

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 28 / 33

  • Stolper-Samuelson Theorem: A Short ProofValue of marginal product conditions for competitive equilibrium

    w1 = p1MP11 = p2MP21 w1/p1 =MP11 w1/p2 =MP21

    w2 = p1MP12 = p2MP22 w2/p1 =MP12 w2/p2 =MP22

    An increase in p = p1/p2 raises w1/w2, and therefore raises theratio of V2/V1 in both industries.

    MPi1 raises and MPi2 falls.

    w1/p1 ↑ w1/p2 ↑w2/p1 ↓ w2/p2 ↓

    Wage of V1 rises relative to both commodity prices.

    Wage of V2 falls relative to both commodity prices.

    ŵ1 > p̂1 > p̂2 = 0 > ŵ2

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 29 / 33

  • Stolper-Samuelson Theorem: A Short ProofValue of marginal product conditions for competitive equilibrium

    w1 = p1MP11 = p2MP21 w1/p1 =MP11 w1/p2 =MP21

    w2 = p1MP12 = p2MP22 w2/p1 =MP12 w2/p2 =MP22

    An increase in p = p1/p2 raises w1/w2, and therefore raises theratio of V2/V1 in both industries.

    MPi1 raises and MPi2 falls.

    w1/p1 ↑ w1/p2 ↑w2/p1 ↓ w2/p2 ↓

    Wage of V1 rises relative to both commodity prices.

    Wage of V2 falls relative to both commodity prices.

    ŵ1 > p̂1 > p̂2 = 0 > ŵ2

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 29 / 33

  • Stolper-Samuelson Theorem: A Short ProofValue of marginal product conditions for competitive equilibrium

    w1 = p1MP11 = p2MP21 w1/p1 =MP11 w1/p2 =MP21

    w2 = p1MP12 = p2MP22 w2/p1 =MP12 w2/p2 =MP22

    An increase in p = p1/p2 raises w1/w2, and therefore raises theratio of V2/V1 in both industries.

    MPi1 raises and MPi2 falls.

    w1/p1 ↑ w1/p2 ↑w2/p1 ↓ w2/p2 ↓

    Wage of V1 rises relative to both commodity prices.

    Wage of V2 falls relative to both commodity prices.

    ŵ1 > p̂1 > p̂2 = 0 > ŵ2

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 29 / 33

  • Stolper-Samuelson Theorem: A Short ProofValue of marginal product conditions for competitive equilibrium

    w1 = p1MP11 = p2MP21 w1/p1 =MP11 w1/p2 =MP21

    w2 = p1MP12 = p2MP22 w2/p1 =MP12 w2/p2 =MP22

    An increase in p = p1/p2 raises w1/w2, and therefore raises theratio of V2/V1 in both industries.

    MPi1 raises and MPi2 falls.

    w1/p1 ↑ w1/p2 ↑w2/p1 ↓ w2/p2 ↓

    Wage of V1 rises relative to both commodity prices.

    Wage of V2 falls relative to both commodity prices.

    ŵ1 > p̂1 > p̂2 = 0 > ŵ2

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 29 / 33

  • Stolper-Samuelson Theorem: A Formal ProofStart from equation (5) from zero profit condition,[

    a11 a12a21 a22

    ] [dw1dw2

    ]=

    [dp1dp2

    ](5)

    Rewrite the system of equation into[V11X1

    ]dw1 +

    [V12X1

    ]dw2 = dp1[

    V21X2

    ]dw1 +

    [V22X2

    ]dw2 = dp2

    [w1V11p1X1

    ]dw1w1

    +[w2V12p1X1

    ]dw2w2

    = dp1p1[w1V21p2X2

    ]dw1w1

    +[w2V22p2X2

    ]dw2w2

    = dp2p2(20)

    The terms in brackets are the shares of each factor’s earnings (j) inthe total revenue of the industry (i), denoted by θij , and 0 < θij < 1.

    [θ11 θ12θ21 θ22

    ] [ŵ1ŵ2

    ]=

    [p̂1p̂2

    ](21)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 30 / 33

  • Stolper-Samuelson Theorem: A Formal ProofStart from equation (5) from zero profit condition,[

    a11 a12a21 a22

    ] [dw1dw2

    ]=

    [dp1dp2

    ](5)

    Rewrite the system of equation into[V11X1

    ]dw1 +

    [V12X1

    ]dw2 = dp1[

    V21X2

    ]dw1 +

    [V22X2

    ]dw2 = dp2

    [w1V11p1X1

    ]dw1w1

    +[w2V12p1X1

    ]dw2w2

    = dp1p1[w1V21p2X2

    ]dw1w1

    +[w2V22p2X2

    ]dw2w2

    = dp2p2(20)

    The terms in brackets are the shares of each factor’s earnings (j) inthe total revenue of the industry (i), denoted by θij , and 0 < θij < 1.[

    θ11 θ12θ21 θ22

    ] [ŵ1ŵ2

    ]=

    [p̂1p̂2

    ](21)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 30 / 33

  • Stolper-Samuelson Theorem: A Formal Proof

    Invert the equation system,[θ22/Dθ −θ12/Dθ−θ21/Dθ θ11/Dθ

    ] [p̂1p̂2

    ]=

    [ŵ1ŵ2

    ](22)

    where Dθ ≡ θ11θ22 − θ12θ21 > 0 and 0 < θij < 1.

    The magnitudes and signs of the mapping in (22) are as follows.[> 1 < 0< 0 > 1

    ] [p̂1p̂2

    ]=

    [ŵ1ŵ2

    ](23)

    The S-S Theorem is given formally by the magnification relationships:

    ŵ1 > p̂1 > p̂2 = 0 > ŵ2 ŵ2 > p̂2 > p̂1 = 0 > ŵ1 (24)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 31 / 33

  • Stolper-Samuelson Theorem: A Formal Proof

    Invert the equation system,[θ22/Dθ −θ12/Dθ−θ21/Dθ θ11/Dθ

    ] [p̂1p̂2

    ]=

    [ŵ1ŵ2

    ](22)

    where Dθ ≡ θ11θ22 − θ12θ21 > 0 and 0 < θij < 1.

    The magnitudes and signs of the mapping in (22) are as follows.[> 1 < 0< 0 > 1

    ] [p̂1p̂2

    ]=

    [ŵ1ŵ2

    ](23)

    The S-S Theorem is given formally by the magnification relationships:

    ŵ1 > p̂1 > p̂2 = 0 > ŵ2 ŵ2 > p̂2 > p̂1 = 0 > ŵ1 (24)

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 31 / 33

  • Stolper-Samuelson Theorem: Policy Implication

    There will be political fights over changes in trade policy.

    While free trade results in aggregate gains in income, those gainsare very unevenly distributed. Some factor owners generally lose.

    This is in turn the source of considerable political controversy overprotection and liberalization

    A country’s scarce factors may lose following trade liberalization.

    There is a sense in which American unskilled workers competeagainst workers in the developing world.

    However, the policy options are not just free trade versusrestricted trade, but possibly include free trade versus variousmeasures to help adversely affected workers (education, training,relocation assistance).

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 32 / 33

  • SummaryA country’s comparative advantage, production and trade aredetermined by underlying factor endowments intersected withtechnologies.

    Relative factor endowments across countries+

    Relative factor intensities across industries=

    Comparative advantage

    Changing the underlying factor endowment can have very biasedeffects on production and trade (Rybczynski).

    Higher savings rates and capital formation in Asia naturally lead toa shift in capital intensive manufacturing toward Asia.

    While free trade results in aggregate gains in income, those gainsare very unevenly distributed. Some factor owners generally lose(Stolper-Samuelson).

    Min Hua & Yiqing Xie (Fudan University) Int’l Econ - H-O Mar. 19, 2014 33 / 33

    OutlineHeckscher-Ohlin Model: an Intuitive ApproachHeckscher-Ohlin Theorem: a Formal ApproachFactor-Price-Equalization TheoremRybczynski TheoremStolper-Samuelson TheoremSummary