Strongly Consistent Self‐Confirming Equilibrium

Fudenberg and Levine (1993a) introduced the notion of self‐confirming equilibrium, which is generally less restrictive than Nash equilibrium. Fudenberg and Levine also defined a concept of consistency, and claimed in their Theorem 4 that with consistency and other conditions on beliefs, a self‐confirming equilibrium has a Nash equilibrium outcome. We provide a counterexample that disproves Theorem 4 and prove an alternative by replacing consistency with a more restrictive concept, which we call strong consistency. In games with observed deviators, self‐confirming equilibria are strongly consistent self‐confirming equilibria. Hence, our alternative theorem ensures that despite the counterexample, the corollary of Theorem 4 is still valid.     

食品供应链中企业与农户短期合作交易契约设计

依据食品供应链中企业与农户间的交易特性,在不完全契约理论框架下,建立了双方承诺不再进行协商的短期合作交易契约设计理论模型。研究结论表明,企业的试验代理人地位是保证农户在第一阶段诚实宣告其类型,从而保证双方专用性投资为最优水平的关键,子博弈精炼纳什均衡的主要限制为,企业支付函数必须为单调函数条件才不会说谎。     

Large Robust Games

With many semi‐anonymous players, the equilibria of simultaneous‐move games are extensively robust. This means that the equilibria survive even if the simultaneous‐play assumption is relaxed to allow for a large variety of extensive modifications. Such modifications include sequential play with partial and differential revelation of information, commitments, multiple revisions of choices, cheap talk announcements, and more.     

企业产品升级投资决策研究

本文应用期权博弈理论研究了在双寡头垄断的市场结构下,企业进行产品升级投资决策的问题,分析了在抢占均衡和同时投资均衡的情况下企业最优产品升级投资时机。研究表明,随着升级投资所导致的成本下降程度的增加,企业升级投资的临界值降低,这一结果与管理实践的直觉相一致,为企业的产品升级投资决策提供了理论指导。     

双寡头R&D合作与非合作时的最优溢出

本文考虑一个双寡头模型,其中两个企业都从事存在溢出的R&D活动。每个企业在产品市场上进行竞争之前,首先确定自己的R&D投资。根据在R&D阶段和产量阶段是否合作,讨论三种情况下使企业利润最大化的溢出水平。在每种情况下,都讨论了溢出的变动对R&D支出、产量、利润、消费者剩余和社会福利的影响。     

Nash均衡、变分不等式和广义均衡问题的关系

主要讨论了Nash均衡问题(NE)与变分不等式(VI)和广义均衡问题(GEP)的关系.给出它们之间解的等价关系,以及与之相应的映射之间单调性的关系.研究结果为进一步研究Nash均衡、广义均衡问题理论及其算法提供了理论依据.     

复杂产品主制造商-供应商协同合作最优成本分担激励研究

当前,“主制造商-供应商”的协同合作模式成为复杂产品的主流生产模式,与传统的制造商供应商合作激励相比,该合作模式更关注供应商的努力水平和长期战略合作,其努力程度决定了复杂产品的生产质量与效率。为激励供应商的努力合作,本文设计努力程度参数,提出了主制造商分摊供应商努力成本的激励策略,建立了基于努力程度的最优成本分摊模型,研究了Nash均衡和Stackelberg均衡两种结构下的激励模式,给出该激励模式下的主制造商分摊供应商研制成本的最优比例、最优努力水平和最优收益。研究结果表明,当供应商的努力程度大于等于努力阀值时,主制造商需分担供应商的努力成本,成本分担大小与供应商努力程度的平方成正比,且受单位收益系数和努力程度收益影响系数的影响。同时,研究表明,在主制造商供应商的协同合作机制中,主从关系的 Stackelberg博弈收益优于Nash均衡收益,应用分析进一步表明,主制造商通过分担供应商努力成本的激励措施可以有效地激励供应商的努力程度,实现在主制造商供应商利益均增长的情况下,达到帕累托改进。本文系统地揭示了主制造商激励供应商的最优成本分担问题,为复杂产品主制造商供应商的长期战略合作激励策略制定提供决策依据。     

Repeated Games Where the Payoffs and Monitoring Structure Are Unknown

This paper studies repeated games with imperfect public monitoring where the players are uncertain both about the payoff functions and about the relationship between the distribution of signals and the actions played. We introduce the concept of perfect public ex post equilibrium (PPXE), and show that it can be characterized with an extension of the techniques used to study perfect public equilibria. We develop identifiability conditions that are sufficient for a folk theorem; these conditions imply that there are PPXE in which the payoffs are approximately the same as if the monitoring structure and payoff functions were known. Finally, we define perfect type‐contingently public ex post equilibria (PTXE), which allows players to condition their actions on their initial private information, and we provide its linear programming characterization.     

The Democratic Political Economy of Progressive Income Taxation

Why do both left and right political parties typically propose progressive income taxation schemes in political competition? Analysis of this problem has been hindered by the two-dimensionality of the issue space. To give parties a choice over a domain that contains both progressive and regressive income tax policies requires an issue space that is at least two-dimensional. Nash equilibrium in pure strategies of the standard two-party game, whose players have complete preferences over a two-dimensional policy space, generically fails to exist. I introduce a new equilibrium concept for political games, based on the fact of factional conflict within parties. Each party is supposed to consist of reformists, militants, and opportunists: each faction has a complete preference order on policy space, but together they can only agree on a partial order. Nash equilibria of the two-party game, where the policy space consists of all quadratic income tax functions, and each party is represented by its partial order, exist, and it is shown that, in such equilibria, both parties propose progressive income taxation.     

Computing Normal Form Perfect Equilibria for Extensive Two‐Person Games

This paper presents an algorithm for computing an equilibrium of an extensive two‐person game with perfect recall. The method is computationally efficient by virtue of using the sequence form, whose size is proportional to the size of the game tree. The equilibrium is traced on a piecewise linear path in the sequence form strategy space from an arbitrary starting vector. If the starting vector represents a pair of completely mixed strategies, then the equilibrium is normal form perfect. Computational experiments compare the sequence form and the reduced normal form, and show that only the sequence form is tractable for larger games.     

Bertrand模型与超模博弈

将近年来博弈论中出现的一种新的研究方法--超模博弈理论应用于Bertrand寡头博弈中,对于具有一般成本函数的差异产品的Bertrand寡头博弈,当企业的策略只是选择价格水平时,比较了博弈为超模和对数超模博弈的充分条件,表明虽然一个对数超模博弈一定是拟超模的,因而较超模博弈的适用范围更广泛,但二者的充分条件之间不具备可比性,即不能由其中一个推出另外一个.同时既使该博弈既不是超模的也不是对数超模的,仍可能存在对利润函数的其它单调转换使博弈成为超模的.当边际生产成本为常数时,给出了具体的反例.当企业的策略为同时选择价格和广告水平,且企业的边际生产成本为常数时,表明在一般的假设下博弈为超模博弈,从而说明了为什么通常情况下较高的广告水平对应着较高的价格.     

A Quantitative Theory of Unsecured Consumer Credit with Risk of Default

We study, theoretically and quantitatively, the general equilibrium of an economy in which households smooth consumption by means of both a riskless asset and unsecured loans with the option to default. The default option resembles a bankruptcy filing under Chapter 7 of the U.S. Bankruptcy Code. Competitive financial intermediaries offer a menu of loan sizes and interest rates wherein each loan makes zero profits. We prove the existence of a steady‐state equilibrium and characterize the circumstances under which a household defaults on its loans. We show that our model accounts for the main statistics regarding bankruptcy and unsecured credit while matching key macroeconomic aggregates, and the earnings and wealth distributions. We use this model to address the implications of a recent policy change that introduces a form of “means testing” for households contemplating a Chapter 7 bankruptcy filing. We find that this policy change yields large welfare gains.     

Noisy Stochastic Games

This paper establishes existence of a stationary Markov perfect equilibrium in general stochastic games with noise—a component of the state that is nonatomically distributed and not directly affected by the previous period's state and actions. Noise may be simply a payoff‐irrelevant public randomization device, delivering known results on the existence of correlated equilibrium as a special case. More generally, noise can take the form of shocks that enter into players' stage payoffs and the transition probability on states. The existence result is applied to a model of industry dynamics and to a model of dynamic electoral competition.     

Discounted Stochastic Games With No Stationary Nash Equilibrium: Two Examples

We present two examples of discounted stochastic games, each with a continuum of states, finitely many players, and actions, that possess no stationary equilibria. The first example has deterministic transitions—an assumption undertaken in most of the early applications of dynamics games in economics—and perfect information, and does not possess even stationary approximate equilibria or Markovian equilibria. The second example satisfies, in addition to stronger regularity assumptions, that all transitions are absolutely continuous with respect to a fixed measure—an assumption that has been widely used in more recent economic applications. This assumption has been undertaken in several positive results on the existence of stationary equilibria in special cases, and in particular, guarantees the existence of stationary approximate equilibria.     

生产能力限制下价格Stackelberg博弈模型

生产能力限制条件下,同质产品市场中两企业以价格为决策变量进行Stackelberg竞争,采取有效配给规则。两企业对称情况下,生产能力较小时模型存在唯一的子博弈精炼纳什均衡,两企业销量达到自身生产能力,得到相同收益;生产能力较大时,追随企业匹配领头企业的价格,博弈存在后动优势。分析了领头企业生产能力大于追随企业的不对称情形,并给出相应均衡。算例分析表明,企业价格竞争的前提是充分大的供给能力,追随企业应在领头企业生产能力较大时进入市场。     

股票市场短期时间序列投机对经理投资行为的影响

公司投资行为受股票市场投机影响,投机性时间序列的实质是影响信息收集行为,股市短期时间序列投机者选择接收关于外生震荡不确定性的私人信息,博弈经理投资决策并对经理投资行为产生影响。本文基于信息结构研究股票市场短期时间序列投机对经理投资行为的影响,分析股票市场博弈均衡和经理有效均衡行为,阐明经理低效率投资决策行为的实质。     

审计合谋的一个博弈均衡分析框架

当前审计环境中,审计合谋现象普遍存在,双重审计制度可以看作是阻止审计合谋的一种制度设计.在分析审计合谋成因的基础上,建立了一个包括引入第二个审计师的概率因子、融合外部监督惩罚与激励机制的博弈模型,对阻止审计合谋的条件进行了均衡分析.研究结果显示,当外部监督惩罚力度强化后与适当的激励机制存在时,双重审计制度有利于降低对审计师的监督成本,从而为其实施提供了理论依据;从多期博弈角度看,这一制度还有利于削弱审计师的"合谋偏好",最终使双重审计回归到单一审计路线上来,节约对审计师的社会监督成本.     

两阶段基于信号博弈的声誉模型

建立了一个两时期基于信号博弈的声誉模型. 有两个参与人进行博弈,拥有私人信息的 参与人叫发送者,另一个不拥有私人信息的叫接收者;该声誉模型研究L 类(低能力类型) 发 送者是否有动机在第一时期建立声誉. 证明显示,如果L 类发送者在第一时期建立声誉,则他 在第二时期的最优信号更大,在第一时期的效用更小,但是,他将在第二时期获得更高的效用.     

有限战略式博弈纯战略均衡求解的新算法

针对现有寻找有限战略式博弈纯战略均衡方法的缺陷,本文证明了一个战略组合是纯战略蚋什均衡的充分必要条件,并根据该条件提出的求解此类博弈模型的纯战略均衡一个算法,最后用一个算例验证了该算法的有效性.     

Threshold Conditions for the Persistence of Plague Transmission in Urban Rats

In this article we derive a mathematical expression characterizing the tendency for Yersinia pestis, the etiologic agent of plague, to become established in an urban rat population upon introduction, and evaluate this risk for several cities. The expression gives a threshold condition for the persistence of Y. pestis transmission in terms of measurable attributes of a local urban rat population: the average flea density and the rat colony size. If the local rat and flea populations exceed this threshold, plague circulation is predicted to continue; if not, it will burn out of its own accord. This expression may be used to evaluate both the vulnerability of a specific neighborhood and the effect of pest control strategies upon that vulnerability.