Multiproduct Quality Competition:Fighting Brands and Product Line Pruning
构建了一个多产品垄断与双寡头模型，解释企业为何采用“战斗品牌”和“产品线修剪”策略，并给出垄断者只卖单一产品的条件，对研究产品线竞争的经济学者有参考价值。
Firms selling multiple quality-differentiated products frequently alter their product lines when a competitor enters the market. We present a model of multiproduct monopoly and duopoly using a general “upgrades” approach that yields a powerful analytical framework. We provide an explanation for the common strategies of using “fighting brands” and of product line “pruning.” The optimal strategy depends on whether entry prompts an incumbent to expand or contract its total output. We also present a general condition that guarantees that a monopolist will sell but a single product. Our model addresses other issues, including intertemporal price discrimination and “damaged goods.”