《国际经济学》课程教学课件（讲稿）第4章 供求、提供曲线与贸易条件 Demand and Supply, Offer Curves, and the Terms of Trade

Chapter 4:Demand and Supply,Offer Curves,and the Terms of Trade（供求、提供曲线与贸易条件) Key terms of this charpter: offer curves reciprocal demand curves 提供曲线（相互需求曲线） ■terms of trade(贸易条件) ■general equilibrium model(一般均衡模型)

1 Chapter 4：Demand and Supply, Offer Curves, and the Terms of Trade（供求、提供曲线与贸易条件） Key terms of this charpter: offer curves（ reciprocal demand curves ） 提供曲线（相互需求曲线） terms of trade（贸易条件） general equilibrium model（一般均衡模型）

4.2 The Equilibrium-Relative Commodity Price with Trade-Partial Equilibrium Analysis (贸易均衡相对商品价格的局部均衡分析) Partial Equilibrium Analysis:the study of individual decision-making units(such as firm or nation)in isolation (i.e.,abstracting from all the interconnections that exist between the firm or nation and the rest of the economy or world) 局部均衡分析：孤立地研究个别决策者（公司或国家）的学科 (即从公司、国家和世界经济的其他部分中抽象出来进行研究)。 2

2 4.2 The Equilibrium-Relative Commodity Price with Trade-Partial Equilibrium Analysis （贸易均衡相对商品价格的局部均衡分析） Partial Equilibrium Analysis：the study of individual decision-making units (such as firm or nation) in isolation (i.e., abstracting from all the interconnections that exist between the firm or nation and the rest of the economy or world). 局部均衡分析：孤立地研究个别决策者（公司或国家）的学科 （即从公司、国家和世界经济的其他部分中抽象出来进行研究）

A图 B图 C图 A国的X商品市场 X商品的国际贸易 B国的X商品市场 Supply curve of exports 出口供给曲线 P 出可 B 进口 D Demand curve of imports 进口需求曲线 X 当Px/Py>P,时，A国在A图中对商品X的额外供给形成了A国出口商品X的 供给曲线，即B图中的S。 同样，当Px/Py<P3时，B国在C图中对商品X的额外需求形成了B国进口商 品X的需求曲线，即B图中的D。 B图表明，Px/P=P2时，A国X的出口量=B国X的进口需量，贸易均衡。 3

3 当PX / PY > P1 时，A国在A图中对商品X的额外供给形成了A国出口商品X的 供给曲线，即B图中的S。 同样，当PX / PY < P3 时，B国在C图中对商品X的额外需求形成了B国进口商 品X的需求曲线，即B图中的D。 B图表明， PX / PY = P2 时， A国X的出口量=B国X的进口需量，贸易均衡。 Supply curve of exports 出口供给曲线 Demand curve of imports 进口需求曲线

4.3A Origin and Definition of Offer Curves 提供曲线的起源与定义 offer curves reciprocal demand curves ) how much of its import commodity a nation demands to be willing to supply various amounts of its export Commodity,or the willingness of the nation to import and export at various relative commodity prices 提供曲线（相互需求曲线）：一国为了进口其需要的某一数量的商品 而愿意出口的商品的数量。或者说是一国在不同的相对商品价格水平 下所愿意进口和出口的商品数量

4 4.3A Origin and Definition of Offer Curves 提供曲线的起源与定义 offer curves （ reciprocal demand curves ）： how much of its import commodity a nation demands to be willing to supply various amounts of its export Commodity, or the willingness of the nation to import and export at various relative commodity prices. 提供曲线（相互 需求曲线 )：一国为了进口其需要的某一数量的商品 而愿意出口的商品的数量。或者说是一国在不同的相对商品价格水平 下所愿意进口和出口的商品数量

4.3B Derivation and Shape of the Offer Curves of Nation 1 A国 Y 100 A国提供曲线 80 P.=1 60 60- 45 40 P,= 2 20 20 H P,= 10 30 50↑70 95 130 20 60 Figure 4.3 Derivation of the Offer Curves of Nation 5

5 Figure 4.3 Derivation of the Offer Curves of Nation 4.3B Derivation and Shape of the Offer Curves of Nation 1 1

4.4 The Equilibrium-Relative Commodity Price with Trade-General Equilibrium Analysis (贸易均衡相对商品价格的一般均衡分析) General Equilibrium Analysis:the study of the interdependence that exists among all markets in the economy. 一般均衡分析：研究存在于经济中各市场之间的内部依存关系。 6

6 4.4 The Equilibrium-Relative Commodity Price with Trade-General Equilibrium Analysis （贸易均衡相对商品价格的一般均衡分析） General Equilibrium Analysis：the study of the interdependence that exists among all markets in the economy. 一般均衡分析：研究存在于经济中各市场之间的内部依存关系

A国 P=P。= B国 60。 50 H 20 10 203040 5060 Figure 4.5 Equilibrium-Relative Commodity Price with Trade The offer curves intersect at point E,defining the equilibrium- relative commodity price Px/Py=PB=PB:=1

7 Figure 4.5 Equilibrium-Relative Commodity Price with Trade The offer curves intersect at point E, defining the equilibrium￾relative commodity price P X / P Y = P B= PB’ = 1

4.5 Relationship between General and Partial Equilibrium Analyses Both Figure 4.5 and Figure 4.6 are derived from the nation's production frontier and indifference map. Figure 4.5 refers to general equilibrium analysis and considers all markets together. Figure 4.6 refers to partial equilibrium analysis and utilizes D and S curves,does not consider these repercussions and the connections that exist between the market for commodity X and the market for all other commodities in the economy. 8

8 4.5 Relationship between General and Partial Equilibrium Analyses Figure 4.5 refers to general equilibrium analysis and considers all markets together. Figure 4.6 refers to partial equilibrium analysis and utilizes D and S curves, does not consider these repercussions and the connections that exist between the market for commodity X and the market for all other commodities in the economy. Both Figure 4.5 and Figure 4.6 are derived from the nation’s production frontier and indifference map

4.6A Definition and Measurement of the Terms of Trade(贸易条件的定义和度量) Terms of Trade:the ratio of the price of its export commodity to the price of its import commodity. 贸易条件(TOT):一国出口商品价格(P)和该国进口商品价 格（Pm)的比值。 例如，对于我们讨论的A国就是Px/PY,B国就是PPx。两国世 界中，互为倒数。 多商品时，TOT=P/Pm=∑X*Pxi/∑M*Pmi P/Pm上升，贸易条件改善；PIPm下降，贸易条件恶化。 9

9 4.6A Definition and Measurement of the Terms of Trade（贸易条件的定义和度量） 多商品时， TOT= P x/ P m = ∑ Xi*P Xi / ∑ Mi*P mi 贸易条件（TOT ）:一国出口商品价格（ P x）和该国进口商品价 格（ P m ）的比值。 例如， 对于我们讨论的 A国就是 P X/ P Y，B国就是 P Y/P X。两国世 界中，互为倒数。 Terms of Trade：the ratio of the price of its export commodity to the price of its import commodity. P x/ P m上升，贸易条件改善； P x/ P m下降，贸易条件恶化