Of course there should exist the manufacturing sector of increasing returns to scale. This means that the scale economies at the plant level would make each variety of products be produced by a single plant in a single region. 当然,需要有规模收益递增的制造业部门的存在,这意味着工厂水平的规模经济将使任何制造业产品只在单一位置的一个工厂进行生产。