Product Assortment in a Triopoly
研究为何高端产品（如超高端冰淇淋）的生产商提供的品种比低端产品更少，通过三寡头博弈模型分析价格和产品组合的纳什均衡，揭示质量、价格敏感度、品种成本等因素对品种决策的影响。
Producers of super-premium ice cream, such as Häagen-Dazs, offer a smaller assortment of flavors than the producers of lesser quality ice cream. Examples of this phenomenon can be found in other industries as well. In many industries, the producers of higher-quality products offer a smaller assortment of flavors, colors, sizes, patterns, textures, fragrances, tones, styles, models, designs, types or other options. This paper explores when and why producers of super-premium products should find it profitable to offer a smaller assortment than the producers of nonpremium products. We derive a Nash equilibrium both on prices and product assortments for a triopoly. At the Nash equilibrium, we show that additional product quality, increased consumer price-sensitivity and greater assortment costs discourages product assortment. We also show that a larger market potential, greater competitive costs and sharper competition encourage more assortment by the super-premium producer.