Entry Barriers and Economic Welfare
研究准古诺市场中企业数量与经济福利的关系，发现自由进入下的企业数量过多，即使政府只能调控数量而无法干预定价，这一结论依然成立。
The relationship between economic welfare and the number of firms in a quasi-Cournot market is examined. In the first place, we presuppose the existence of a strong ("first-best") government that can enforce the marginal-cost principle to the firms along with regulating the number of firms. It is shown that there exist excessive number of firms at the free-entry quasi-Cournot equilibrium vis-à-vis the "first-best" welfare maximizing number of firms. The thrust of this result essentially survives even if we replace a Utopian "first-best" government by a "second-best" government that leaves the firms to pursue their respective profit maximization freely and engages solely in regulating the number of firms. It can be shown that the excess entry prevails again in this "second-best" world.