产品多样性与企业区位选择

Location Choice of Multiple Product Firms

在一个“线性城市”市场中有两个企业，每个企业生产两种产品，且每个企业在其中一种产品上具有垄断力量，而在另外一种产品上与其他企业竞争。本文讨论这个市场上企业的最优选址问题，研究表明，企业选址与垄断类消费者和竞争类消费者的比例有关。当垄断类消费者的比例足够大时，企业选择集聚；当竞争类消费者的比例足够小时，企业选择尽可能远离对方；当二者数量相差不大时，企业将选择中间状态。与社会最优选址相比，两个企业之间的距离既可能过远也可能过近。

This paper analyzes the firm location problem in a ＂linear city＂ model that involves a mixture of monopolies for two products and duopoly for another product. It is shown that the equilibrium locations depend on the ratio of brand-loyal consumers to brand switchers. If the ratio is high enough, firms will agglomerate at the center of the market. If the ratio is low enough, they will choose the endpoints of the market. If the ratio is in the medium range, firms will choose inner points to locate their plants. Compared to the social optimal pattern of locations, the distance between two firms could be too large or too small.