On the Generic (Im)Possibility of Full Surplus Extraction in Mechanism Design
指出，在凸先验族中，通用先验不允许完全剩余提取，除非每个玩家的信念能唯一确定其偏好；特别地，有限类型空间和通用类型空间中的通用先验均无法实现完全剩余提取。
A number of studies, most notably Crémer and McLean (1985, 1988), have shown that in generic type spaces that admit a common prior and are of a fixed finite size, an uninformed seller can design mechanisms that extract all the surplus from privately informed bidders. We show that this result hinges on the nonconvexity of such a family of priors. When the ambient family of priors is convex, generic priors do not allow for full surplus extraction provided that for at least one prior in this family, players' beliefs about other players' types do not pin down the players' own preferences. In particular, full surplus extraction is generically impossible in finite type spaces with a common prior. Similarly, generic priors on the universal type space do not allow for full surplus extraction. Copyright The Econometric Society 2006.