Cooperative Management of Groundwater Resources in the Presence of Environmental Externalities

This paper investigates how cooperation among users can achieve a better management of groundwater in the presence of environmental externalities. Cooperation allows users to internalize the damages caused by their activities and reduce extractions. The paper develops a game theoretical framework to assess the value of cooperation in an aquifer that is divided into three sub-aquifers that are being overly exploited. Two types of externalities are modeled: first, water extractions in each sub-aquifer impact water levels in neighboring sub-aquifers (extraction externality). Second, the three sub-aquifers are also connected to an ecosystem and thus decisions in each sub-aquifer affect the health of the ecosystem (environmental externality). A cooperative game theory model is applied. The model empirically shows how the uncontrolled extractions in each sub-aquifer affects neighboring groundwater users but also cause severe impacts to the linked ecosystem. The model is tested empirically in one of the most important aquifers in Spain, the Eastern la Mancha aquifer. The results illustrate how both extraction and environmental externalities interact in affecting the likelihood of cooperation among the users. The paper estimates the value of cooperation and its stability with and without the environmental externality.     

On Clustering in the Location of R&D: Statics and Dynamics

Empirical analyses of research and development find strong evidence that these activities tend to cluster geographically. Clusters are thought to emerge from the presence of localized positive externalities. This paper presents a model of this clustering behaviour. We find that phase changes in clustering exist both as the strength of local externalities changes and as the degree of heterogeneity among firms changes. The dynamics of the system are examined as it responds to shocks to the size of the market for R&D output, and the length scale of the spatially dependent externalities. Dynamic responses take place in two distinct stages: a rapid response to the change in market systems which takes place throughout the space, with litlle regard to externality effects; followed by a slow re-agglomeration process as producers change their spatial decisions to lower the costs of the new production level.     

First-best health policy in vaccine markets with health and network externalities

This paper considers an oligopolistic market for a vaccine, characterized by negative network effects, which stem from the free-riding behavior of individuals engaged in a vaccination game. Vaccine markets often suffer from three imperfections: high concentration, network effects, and a health externality (contagion). The first conclusion of the paper is that the negative network externality is important as a market distortion, as it may lead to significant welfare losses. The second and main part of the paper develops a two-part per-unit subsidy scheme that a social planner could use to target both consumers and producers of vaccines. The scope of such a subsidy scheme to induce the firms to produce the first-best output without network effects (which is the most ambitious first-best target) is investigated. In many cases, while the first-best is attainable, it requires negative prices for vaccines, which amounts to rewarding consumers to induce them to vaccinate.     

Should the Carbon Price Be the Same in All Countries?

International differences in fuel taxation are huge, and may be justified by different local negative externalities that taxes must correct, as well as by different preferences for public spending. In this context, should a worldwide uniform carbon tax be added to these local taxes to correct the global warming externality? We address this question in a second best framework à la Ramsey, where public goods have to be financed through distortionary taxation and the cost of public funds has to be weighted against the utility of public goods. We show that when lump‐sum transfers between countries are allowed for, the second best tax on the polluting good may be decomposed into three parts: one, country‐specific, dealing with the local negative externality, a second one, country‐specific, dealing with the cost of levying public funds, and a third one, global, dealing with the global externality and which can be interpreted as the carbon price. Our main contribution is to show that the uniformity of the carbon price should still hold in this second best framework. Nevertheless, if lump‐sum transfers between governments are impossible to implement, international differentiation of the carbon price is the only way to take care of equity concerns.     

Delegation versus centralization: The role of externalities

We study a simple contracting game with a principal and two agents. Contracts exert externalities on non-contractors. The principal can either contract both agents in a centralized manner, or delegate one agent to contract the other. We show that the choice of the principal depends on the sign of the externality. If this is positive, the principal prefers to delegate as long as the agency costs are not too high; if the externality is negative, the principal prefers to centralize for all sizes of agency costs.     

Thematic Clubs and the Supremacy of Network Externalities

We explore the issue of minorities' survival in the presence of positive network externalities. We rely on a simple example of thematic clubs to illustrate why and how such survival problems might appear, first considering the case of simple‐network effects (fully anonymous externalities) and then the case of cross‐network effects (type‐dependent externalities). In both cases, the analysis is framed as a simple noncooperative game with a continuum of players and binary action sets. There is a unique and interior Nash equilibrium under mild network effects and two corner equilibria under strong network effects, with one club driven out. A utilitarian planner would accentuate the clustering effects of network externalities, and call for the disappearance of the minority club more often than the noncooperative solution. A simple myopic learning algorithm capturing the progression of network lock‐in effects is studied.     

旅游网络与电子商务网站外部性互补的分析

结合电子商务网站,旅游网络表现出强烈的外部性,本文分析旅游网络的基本外部性、客户黏度、网络弹性、客户预期和费用率等核心元素,总结出旅游网络外部性估算办法,对照外部性特征,由实际出发,提出旅游企业进行差异化营销的三个核心环节：创新图存、虚拟协同和分工细化,以充分利用旅游网络的外部性特征,提高旅游业务活力。     

Binary Games with State Dependent Stochastic Choice

This paper studies a stochastic equilibrium selection model for binary coordination games. Players switch strategies stochastically so that the mistake probabilities are fully dependent on the population states. A probabilistic behavior is said to be aspiration (imitation, resp.) oriented if strategy switches are mainly driven by the aspiration (imitation, resp.) effect. In general, a strategy switch by one player generates externalities on others. Strategies in a coordination game can be classified according to the relative magnitude of their externality effects. It is shown that the selection outcome for a linear coordination game is determined in a specific way by the balance of the risk dominance, the aspiration/imitation, and the externality effects. It is also shown that an aspiration (imitation, resp.) oriented behavior tends to select payoff dominant (maxmin, resp.) equilibrium and that risk dominant equilibrium is always selected if and only if the aspiration and the imitation effects exactly cancel each other out, which in turn makes the selection process insensitive to externality effects. Journal of Economic Literature Classification Number: C72.     

A testable model of consumption with externalities

This paper presents a nonparametric model of interdependent preferences, where an individual's consumption may act as an externality on the preferences of other consumers. We assume that individual price consumption data is observed for all consumers. It is known that the general consumption model with externalities imposes few restrictions on the observed data, where the consistency requirement is Nash rationalizability. We motivate potential games as an important sub class of games where the family of concave potential games is refutable and imposes stronger restrictions on observed data. We use this framework to extend the analysis of Brown and Matzkin [D. Brown, R. Matzkin, Testable restrictions on the equilibrium manifold, Econometrica 64 (1996) 1249-1262] on refutable pure exchange economies to pure exchange economies with externalities. Finally, we discuss an application of this model to inter-household consumption data.     

网络外部性下基于投资溢出的企业合作研发博弈模型

本文建立了网络外部性环境下基于投资溢出的企业合作研发博弈模型,研究了企业合作研发策略,分析了网络外部性、兼容性以及投资溢出等对企业合作研发动机、企业利润和社会福利等的影响。研究表明,合作研发能提高企业利润和社会福利;兼容性较大或外部性较小时,提高产品外部性会增强企业合作研发意愿;提高兼容性或投资溢出则始终会增强企业合作研发意愿,提高企业利润和社会福利。因此,政府应鼓励企业生产高网络外部性和高兼容性的产品,并增强投资溢出效应,激励企业投入更多研发资源,提高企业利润和社会福利。     

Dynamic Games of Environmental Policy in a Global Economy: Taxes versus Quotas

The effects of environmental policy on the global environment as an international public good with a stock externality and national welfare are examined in a model with trade in a polluting commodity. The welfare effects of environmental policy, decomposed into terms of trade, abatement cost, and environmental damage effects, induce governments to adopt a strategic use of their policy measures. In the absence of international cooperation on environmental policy, it is demonstrated that the emission tax game brings about larger strategic distortions than the emission quota game.     

Consumption externality and indeterminacy under increasing returns to scale and endogenous capital depreciation

This paper incorporates negative consumption externality embodying “jealousy” and “running away from the Joneses” into Guo and Lansing (2007)'s model with production externality and endogenous depreciation, and examines how consumption externality helps to generate equilibrium indeterminacy together with production externality. Specifically, the existence of consumption externality reduces the upper and lower bounds of production externality for local indeterminacy, and when the degree of consumption externality increases, the upper and lower bounds of production externalities for local indeterminacy are both reduced.     

When redistribution makes personalized pricing of externalities useless

We consider a standard optimal taxation framework in which consumers' preferences are separable in consumption and labor and identical over consumption, but are affected by consumption externalities. For every nonlinear, income-dependent pricing of goods there is a linear pricing scheme, combined with an adjusted income tax schedule, that leaves all consumers equally well-off and weakly increases the government's budget. The result depends on whether a linear pricing scheme exists that keeps the aggregate amount of consumption at its initial level observed under nonlinear pricing. We provide sufficient conditions for the assumption to hold. If adjusting the income tax rate is not available, personalized prices for an externality can enhance social welfare if they are redistributive, that is, favor consumers with a larger marginal social value of income.     

Price competition when consumer behavior is characterized by conformity or vanity

It has long been recognized that the pleasure of consuming a good may be affected by the consumption choice of other consumers. In some cases, social pressures may lead to conformity; in some others, individuals may feel the need of exclusiveness under the form of vanity. Such externalities have proven to be important in several markets. However, the market implication of these externalities are still unclear. To investigate them, we propose to combine the consumption externality model and the spatial duopoly model. When conformity is present but not too strong, both firms remain in business but price competition is fiercer and results in lower prices. The market share of the large firm increases with the population size; as the population keeps rising, the large firm may serve the entire market and set a price that has the nature of a limit price. When conformity is strong enough, different equilibria may exist. In most of these equilibria, a single firm captures the whole market. At the other extreme, when vanity is at work, price competition is relaxed.     

创新能力、空间依赖与长三角城市群增长核心演化

城市群经济系统发展过程中,核心城市的增长极化与扩散作用是推动城市群协同发展的关键机制。创新能力、要素集聚与扩散形成的区际空间外部性使得城市群增长核心不断演化,并形成系统协同发展的内在动力。长三角城市群核心城市的极化效应呈现出下降趋势,对其主要影响因素的实证分析结果表明：创新分工过程中创新要素集聚与创新溢出、空间依赖都对城市极化效应具有显著影响。因此,政策导向应从强化城市间创新分工、充分利用创新过程的空间外部性、推进城市群协同发展的制度创新等方面着手。     

Household Demand, Network Externality Effects and Intertemporal Price Discrimination

This paper examines the optimality of intertemporal price discrimination when network externality effects are present in the consumption of a durable good. We conduct our study in two settings. In a model with two household types, utilities are dependent on the cumulative proportion of households that have purchased the durable good. Next, in a model with a continuum of household types, we extend the analysis to the case where households consume both a durable good and a stream of non-durable goods. We show that in both settings, the presence of network externalities facilitates a sales strategy with intertemporal price discrimination.     

科技创新财税政策的合理边界研究

科技创新活动存在着知识溢出,具有极强的正外部性,导致市场失灵,这就需要政府在科技创新领域有所作为。根据庇古(Pigou)关于外部性思想的阐述,财税政策是解决外部性问题的重要手段,科技创新领域也不例外,科技创新财税政策的合理边界应由科技创新活动外部性的大小来界定。     

Consumption externalities, production externalities, and efficient capital accumulation under time non-separable preferences

The effects of consumption and production externalities on economic performance under time non-separable preferences are examined both theoretically and numerically. We show that a consumption externality alone has long-run distortionary effects if and only if labor is supplied elastically. With fixed labor supply, it has only transitional distortionary effects. Production externalities always generate long-run distortions, irrespective of labor supply. The optimal tax structure to correct for the distortions is characterized. We compare the implications of this model with those obtained when the consumption externality is contemporaneous. While some of the long-run effects are robust, there are also important qualitative and quantitative differences, particularly along transitional paths.     

Endogenous City Formation with Production Externalities: Existence of Equilibrium

I show that equilibria exist in closed city‐system models with production externalities if firms' production possibilities vary continuously with the source of the externality, are constant returns to scale in own inputs, include inaction, and satisfy free disposal; if firms have to employ their own inputs to produce output; if there is a finite number of firm types; and if some standard conditions on preferences and endowments are satisfied. This is the first model to include production externalities in the fully general equilibrium framework required for endogenous city formation. Thus, this result provides formal support for the conjecture that production externalities lead to urban agglomeration.