An arbitrary number of (ex ante symmetric) firms first choose whether to produce a high-quality or a low-quality product and then, the quantity of product to put on the market. We establish the following results: (1) there exists competition within and across quality segments; (2) firms may be better off producing the low quality if competition within this segment is sufficiently low; (3) a firm’s switch across qualities may benefit all the other firms; (4) there exists a unique partition of the firms between the two quality segments; (5) if high quality has a larger cost-quality ratio, then the equilibrium exhibits vertical differentiation; (6) there may be too much differentiation from the consumers’ point of view.

中文翻译：

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古诺寡头垄断中的内生垂直分割

任意数量的（事前对称）公司首先选择是生产高质量产品还是低质量产品，然后选择投放市场的产品数量。我们得出以下结果：（1）质量细分市场内部和之间存在竞争；(2) 如果该细分市场的竞争足够低，公司可能最好生产低质量的产品；(3) 一个企业的质量转换可能使所有其他企业受益；(4) 在两个质量细分市场之间存在独特的企业划分；(5) 如果高质量的成本质量比较大，则均衡呈现垂直分化；(6) 从消费者的角度来看，可能存在太多差异。