Product Differentiation and Location Choice in a Circular City*
研究了销售替代品或互补品的企业在圆形城市中先选址再在古诺竞争中定产，发现线性与凸性运输成本下存在多种均衡，且互补品企业数量增多时结果与双寡头显著不同。
Abstract. The paper analyzes spatial competition among firms that sell substitute and/or complementary products. The firms first choose locations on the perimeter of a circular city and then compete in quantities (à la Cournot). Both linear and convex (quadratic) transport costs are considered. In general, multiple location equilibria are encountered. Complete agglomeration, partial agglomeration, and complete dispersion are possible. Convex (quadratic) transport cost substantially shrinks the set of equilibria obtained under linear transport cost. In general, the results obtained for a larger number of firms selling complementary products are strikingly different from those obtained under a duopoly.