Grounded by Gravity: A Well-Behaved Trade Model with Industry-Level Economies of Scale
研究行业层面外部规模经济在开放经济中的作用，发现当外部经济强度低于贸易弹性倒数时，模型在摩擦贸易下仍可处理，且所有国家从贸易中获益；外部经济会降低贸易收益，除非该国专门生产高规模经济行业，并放大进一步贸易自由化的收益，除非导致专门生产低规模经济行业。
We propose a model to study the role of industry-level external economies of scale in open economies. If the elasticity governing the strength of external economies is below the inverse of the trade elasticity in each industry, then specialization under frictionless trade is consistent with comparative advantage, the model is tractable even with trade frictions, and all countries gain from trade. External economies lower gains from trade except if the country specializes in industries with high scale economies, and they amplify the gains from further trade liberalization except if it leads to specialization in industries with low scale economies.