Vertical Separation
用一个简单的双寡头模型说明制造商通过独立零售商销售产品（垂直分离）比直接销售给消费者（垂直整合）更有利，因为能诱导竞争对手更友好的行为，并促进制造商之间的合谋。
A simple duopoly model is used to show the advantage to a manufacturer of selling his product through an independent retailer (vertical separation) rather than directly to consumers (vertical integration). Vertical separation is profitable insofar as it induces more friendly behavior from the rival manufacturer. The authors consider the case where franchise fees can be used to extract retailers' surplus. They show that vertical separation is in the collective, as well as individual, interest of manufacturers, and hence facilitates some collusion in the simple setting that they examine.