不同发展阶段、双寡头竞争下的最优贸易政策

本运用非合作博弈思想，分析了本国在经济发展的三个阶段中，在本国和外国企业进行双寡头古诺竞争的情况下，本国最优贸易政策的确定问题。本研究发现：本国企业与外国企业的边际成本是影响最优关税税率的重要因素，并且在经济发展的不同阶段，它们对最优关税税率的作用也不同。     

On a generalized Cournot oligopolistic competition game

We consider a model whereby players compete for a set of shared resources to produce and sell substitute products in the same market, which can be viewed as a generalization of the classical Cournot oligopolistic competition model, or, from a different angle, the Wardrop type routing model. In particular, we suppose that there are K players, who compete for the usage of resources as well as the sales of the end-products. Moreover, the unit costs of the shared resources and the selling prices of the products are assumed to be affine linear functions in the consumption/production quantities. We show that the price of anarchy in this case is lower bounded by 1/K, and this bound is essentially tight, which manifests the harsh nature of the competitive market for the producers.     

Duopoly competition in networks

This paper presents a new approach to modeling competition between firms in network-based industries, i.e. industries where the firms' technology decisions correspond to choices of networks. Industries having this structure include transportation, telecommunications, and some service industries. Competition is studied between two firms who make both network design decisions and price decisions for services. This situation is modeled as a game, an equilibrium solution corresponding to a Nash equilibrium is defined, and properties of the solution are characterized. Necessary and sufficient conditions are shown for equilibrium solutions and existence of equilibrium solutions is demonstrated. Among the results is that each firm will maximize its own profit by minimizing total industry cost of providing services. An example demonstrating results is presented.     

On the uniqueness of Cournot equilibrium in case of concave integrated price flexibility

We consider a class of homogeneous Cournot oligopolies with concave integrated price flexibility and convex cost functions. We provide new results about the semi-uniqueness and uniqueness of (Cournot) equilibria for the oligopolies that satisfy these conditions. The condition of concave integrated price flexibility is implied by (but does not imply) the log-concavity of a continuous decreasing price function. So, our results generalize previous results for decreasing log-concave price functions and convex cost functions. We also discuss the particular type of quasi-concavity that characterizes the conditional revenue and profit functions of the firms in these oligopolies and we point out an error of the literature on the equilibrium uniqueness in oligopolies with log-concave price functions. Finally, we explain how the condition of concave integrated price flexibility relates to other conditions on the price and aggregate revenue functions usually considered in the literature, e.g., their concavity.     

On the Tikhonov Well-Posedness of Concave Games and Cournot Oligopoly Games

The purpose of this paper is to investigate whether theorems known to guarantee the existence and uniqueness of Nash equilibria, provide also sufficient conditions for the Tikhonov well-posedness (T-wp). We consider several hypotheses that ensure the existence and uniqueness of a Nash equilibrium (NE), such as strong positivity of the Jacobian of the utility function derivatives (Ref. 1), pseudoconcavity, and strict diagonal dominance of the Jacobian of the best reply functions in implicit form (Ref. 2). The aforesaid assumptions imply the existence and uniqueness of NE. We show that the hypotheses in Ref. 2 guarantee also the T-wp property of the Nash equilibrium.As far as the hypotheses in Ref. 1 are concerned, the result is true for quadratic games and zero-sum games. A standard way to prove the T-wp property is to show that the sets of -equilibria are compact. This last approach is used to demonstrate directly the T-wp property for the Cournot oligopoly model given in Ref. 3. The compactness of -equilibria is related also to the condition that the best reply surfaces do not approach each other near infinity.     

Dynamical multi-team Cournot game

In this paper we propose two different versions of the multi-team model where a team of two firms compete with another team. The firms in each team help each other. We studied the equilibrium solutions, the conditions of their local asymptotic stability. Some numerical simulations are done.     

On Nash–Cournot oligopolistic market equilibrium models with concave cost functions

We consider Nash–Cournot oligopolistic market equilibrium models with concave cost functions. Concavity implies, in general, that a local equilibrium point is not necessarily a global one. We give conditions for existence of global equilibrium points. We then propose an algorithm for finding a global equilibrium point or for detecting that the problem is unsolvable. Numerical experiments on some randomly generated data show efficiency of the proposed algorithm.     

Stability of the Cournot equilibrium for a Cournot oligopoly model with n competitors

In this paper a Cournot-like model is constructed with an iso-elastic demand function for n competitors. The Cournot equilibrium is constructed for general constant unit costs. Finally, it is proved that for identical unit costs the Cournot point is a sink for two or three competitors and a saddle for more than four players.     

两阶段双寡头垄断市场Hotelling定价模型

激烈的双寡头垄断市场竞争环境下,单一定价和歧视定价成为厂商选择的两大定价策略.考虑到网络外部效用的广泛存在性与对称性,对传统的Hotelling模型加以改进,分价格竞争和策略选择两个阶段,对双寡头垄断厂商的定价策略进行了博弈分析,指出了各种均衡情况及需满足的条件,并验证了歧视定价相对单一定价的边际成本、网络外部效应、消费者对产品的忠诚度等因素对厂商进行定价策略选择的重要影响,为其制定最优定价策略提供了指导.     

寡占市场易逝性产品收入管理的博弈分析

传统的收入管理没有考虑市场竞争的情况。本研究了销售同质易逝品的两家公司的存量控制策略，证明存在纯策略的纳什均衡。通过进一步与垄断(联盟)情况下的比较，得出在竞争状况下商家将为高价顾客预留更多的产品。     

Cournot equilibrium uniqueness via demi-concavity

A family of oligopolies that possess a unique equilibrium was identified in the second authors doctoral dissertation. For such a family, it is therein specified a class of functions-economically related to the price function of a Cournot oligopoly – that satisfy a particular type of quasi-concavity. The first part of the present article (i) conceptualizes that type of quasi-concavity by introducing the notion of demi-concavity, (ii) considers two possible variants and (iii) provides some calculus properties. The second part, by relying on the results on demi-concavity, proves a Cournot equilibrium uniqueness theorem which is new for the journal literature and subsumes various results thereof. A third part shows an example that illustrates the novelty of the result.     

半导体与超晶格的数学模型及其分析Ⅰ:模型

本文论及半导体与超晶格的数学模型方法的一些新近发展动态。介绍了半导体与超晶格的一些背景材料并给出了半导体宏观模型间的层次框架。超晶格中载流子传输的SHE扩散模型也被观察。     

Manifolds of multi-leader Cournot equilibria

We show that the known uniqueness results for leader-follower Cournot games with multiple but identical leaders hinge on the tacit assumption that identical leaders make identical decisions. We illustrate that without this assumption multi-leader Cournot games may well possess nontrivial manifolds of equilibria and discuss the underlying reasons.     

纵向差异化下的双寡头说服性广告竞争

构建了一个纵向差异化下的双寡头说服行广告竞争模型,考查了均衡时双寡头企业的相对市场份额、均衡价格、企业利润及其决定因素,并对其进行比较静态分析,得出了若干有价值的结论,并构造了一个梯形分布的算例来对结论进行了验证.     

Duopoly information sharing with differentiated products

Consider a model where firms own the same technology in linear Cournot duopolies with differentiated products and the slope of the demand curve facing the firm is unknown, containing an own-price effect and a cross-effect. We discuss as follows: whether there is an incentive to share information when firms are symmetrically informed about the random demand. In a two-stage game, for independent goods and complements, it is a Nash equilibrium for firms to put their private information in a common pool.     

Kopel寡头博弈模型的演化分析

利用非线性动力学理论研究了Kopel寡头模型的一类双参数分支情形—1∶4共振.与单参数分支相比,1∶4共振作为单参数分支的退化情形可以描述该双参数分支点邻域内的分支分布问题,利用数值模拟探讨了一些该模型的复杂动力学性质.     

时间序列问题的建模方法和过程

时间序列分析是研究经济学和统计学的一种重要方法,通过分析实际的时间数据序列进行建立数学模型,用来预测序列的未来的发展情况。本文介绍了时间序列的发展概况和基本概念,论述了ARMA模型的自协方差函数、自相关系数、偏自相关函数的特征和Box-Jenkins建模。Box-Jenkins建模方法一般包括模型识别、参数估计、模型适用性检验和预测等步骤,该模型主要运用于单变量、同方差场合的线性模型。通过对模型的进一步研究,明确了模型的定阶与参数估计等问题。     

A nonlinear Cournot duopoly with advertising

This paper aims at studying local and global dynamics in a nonlinear duopoly with quantity-setting firms and non-cooperative advertising investments that affect the degree of (horizontally) differentiated products. It concentrates on persuasive advertising in a model where each firm has limited information and uses a behavioural rule to set the quantity for the subsequent period. By using some mathematical techniques and numerical simulations, our results show the existence of weak (à la Milnor) attractors, multistability and chaotic dynamics. In the long term, firms may continuously shift from states in which they invest in advertising to states in which advertising investment is absent.     

Global bifurcations in a piecewise-smooth Cournot duopoly game

The object of the work is to perform the global analysis of the Cournot duopoly model with isoelastic demand function and unit costs, presented in Puu [2]. The bifurcation of the unique Cournot fixed point is established, which is a resonant case of the Neimark–Sacker bifurcation. New properties associated with the introduction of horizontal branches are evidenced. These properties differ significantly when the constant value is zero or positive and small. The good behavior of the case with positive constant is proved, leading always to positive trajectories. Also when the Cournot fixed point is unstable, stable cycles of any period may exist.