A single product natural monopoly — as defined in the contestability literature — is forced by the "weak invisible hand" to charge an average cost price if the market is perfectly contestable. Furthermore, in the presence of sunk costs, the incumbent firm can realize a profit equal to the sunk cost without inviting entry. Price-sustainable natural monopoly market configurations have been characterized as Bertrand-Nash equilibria for market games involving an incumbent firm and one or more potential entrants [Becker, Journal of Economics and Business, 1994; Knieps and Vogelsang, Bell Journal of Economics, 1982]. In these games, all players, the incumbent and the potential entrants, choose their prices simultaneously. Consequently, potential entrants have to make an entry and pricing decision at the same time.
展开▼
机译：如果市场是完全可竞争的，则单一的产品自然垄断（如可竞争性文献所定义）被“弱无形的手”强迫收取平均成本价格。此外，在存在沉没成本的情况下，在位企业可以在不邀请进入的情况下实现等于沉没成本的利润。价格可持续的自然垄断市场结构的特征是，涉及在位公司和一个或多个潜在进入者的市场博弈的贝特朗·纳什均衡[Becker，《经济与商业杂志》，1994年； Knieps and Vogelsang，《贝尔经济学》，1982年]。在这些游戏中，所有玩家，现任和潜在进入者都同时选择其价格。因此，潜在的进入者必须同时做出进入和定价的决定。
展开▼
