The General Validity of the Law of Comparative Advantage
证明，在多商品世界中，比较优势定律在单个商品层面虽不成立，但若以所有商品的平均值重新表述，该定律仍然有效，并推导出贸易向量与比较优势相对自给自足价格测度向量之间的相关性定理。
It is well known that the law of comparative advantage breaks down when applied to individual commodities or pairs of commodities in a many-commodity world. This paper shows that the law is nonetheless valid if restated in terms of averages across all commodities. Specifically, a theorem and several corollaries are derived which establish correlations between vectors of trade and vectors containing relative-autarky-price measures of comparative advantage. These results are proven in a general many-commodity model that allows for tariffs, transport costs, and other impediments to trade.