Pure joint production and international trade: a note
运用新李嘉图（斯拉法）国际贸易理论分析联合生产系统，发现与单一产品系统不同，国际专业化模式并非总是存在，比较优势法则也非普遍有效，且这些取决于收入分配变量。
This paper applies the principles of the neo-Ricardian (or Sraffian) theory of international trade to certain joint production systems. It is shown that, in contrast with single-product systems, (i) there is not always a pattern of international specialisation, which would entail the increase of the real wage rate in both economies, and (ii) the ‘law of comparative advantage’ has no general validity. Furthermore, not only the existence of such a pattern of specialisation but also the validity of this law depend on the values of the variables of distribution of income. The analysis is wholly based on two of the numerical examples formulated by Bidard in 1997, and further generalised in an elementary way only when this is considered necessary.