Lack of confidence,the zero lower bound,and the virtue of fiscal rules

In the presence of the zero lower bound, standard business cycle models with a Taylor-type monetary policy rule are prone to equilibrium multiplicity. A drop in private sector confidence can drive the economy into a liquidity trap without any change in fundamentals. I show, in the context of a standard New Keynesian model, that it is possible to design Ricardian fiscal spending rules that insulate the economy from such expectations-driven liquidity traps. In the case of price adjustment costs, desirable fiscal rules ensure that a drop in confidence does not lead to a decline in real marginal costs. In the case of nominal wage adjustment costs, desirable fiscal spending rules ensure that a drop in confidence does not lead to a decline in the ratio of the marginal rate of substitution between private consumption and hours worked relative to the real wage rate.     

A model of population distribution,traffic congestion,and neighborhood crowding in a circular city

An idealized static equilibrium model of a circularly symmetric city is presented. The model allows one to compute the spatial distribution of residences, given certain simple and plausible assumptions about the “costs” of transport, housing and neighborhood crowding. The model is chosen so as to guarantee that in first approximation, the residential population distribution which would be considered optimal by a perfect planner is identical to the distribution reached in a push-shove, laissez-faire equilibrium. This aspect of the construction is shown to be related in a simple way to the familiar “external diseconomy” situation in which a free resource is allocated among alternative uses by equating average, rather than marginal products. The existence of an infinite class of models in which the associated planner's optimum and laissez-faire equilibria are equivalent follows naturally from the standard theory of the private and social costs of highway congestion. The model leads naturally to exponentially falling population distributions which exhibit an “urban-suburban” dichotomy, to a particular overall city size, and to an optimal allocation of land between transport and residential uses.     

Spatial externalities and agglomeration in a competitive industry

We introduce spatial spillovers as an externality in the production function of competitive firms operating within a finite spatial domain under adjustment costs. Spillovers may attenuate with distance and the overall externality could contain positive and negative components with the overall effect being positive. We show that when the spatial externality is not internalized by firms, spatial agglomerations may emerge endogenously in a competitive equilibrium. The result does not require increasing returns at the private or the social level, increasing marginal productivity of private capital with respect to the externality, or location advantages. In fact agglomerations may emerge with decreasing returns to scale, declining marginal productivity of private capital with respect to the externality, and no location advantage. The result depends on the interactions between the structures of production technology and spatial effects as shown in the paper. No agglomerations emerge at the social optimum when spillovers are internalized and diminishing returns both from the private and the social point of view prevail. Numerical experiments with Cobb–Douglas and CES technologies and an isoelastic demand confirm our theoretical predictions.     

Spatial discrimination: Bertrand vs. Cournot with asymmetric demands

This paper develops a barbell model a la Hwang and Mai [Hwang, H., and C.C. Mai, 1990, Effects of spatial price discrimination on output, welfare, and location, American Economic Review 80, 567–575.] with homogeneous product and asymmetric demands to compare prices, aggregate profits and social welfare between Cournot and Bertrand competition, and to analyze the firms' equilibrium locations. It focuses on the impacts of the spatial barrier generated from transport costs, and the market size effect resulting from asymmetric demands. It shows that the market-size effect is crucial in determining firms' locations under Cournot competition, but insignificant under Bertrand competition. Moreover, the equilibrium price of the large market and the aggregate profits are lower but the social welfare is higher under Cournot competition than under Bertrand competition if one of the markets is sufficiently large and the transport cost is high.     

Home market effects with endogenous costs of production

In a standard imperfect competition model, we endogenize the costs of production of firms in the increasing returns sector (IRS) via process R&D. We show that firms in the larger region in terms of demand invest more in R&D (i.e.: they are bigger in size and have lower marginal costs) than firms in the smaller region, since the former exploit larger economies of scale in production to pay for the costs of R&D. As a result, when the return on R&D is high, the larger region does not employ disproportionately more labor nor attracts a disproportionately larger share of firms in the IRS in relation to share of demand it hosts, i.e.: negative home market effects (HMEs) in employment and in the number of firms. When this occurs, only partial agglomeration of the IRS in the larger region is sustainable in equilibrium. Even so, the larger region always runs trade surplus in the IRS, i.e.: HME in trade patterns.     

Bertrand oligopoly in a spatial context: The case of quantity independent transportation costs

The theory of spatial competition [for a review, see Gabszewicz and Thisse (1985)] is usually based on the assumption of transportation costs which are proportionate to distance and quantity. In reality, however, there exist frequently considerable economies of scale, especially with respect to the conveyed quantity of goods. A good case in point is transportation cost incurred by a consumer patronizing a shopping area. Cost economies of scale will in general influence consumers' optimal choice with respect to quantities and best market places. In the extreme, consumers' outlays on transportation can be considered independent of the purchased quantity, but approximately proportionate to distance. In the present paper, the impact of this assumption on spatial competition is analysed. It will be shown, that existence and uniqueness of spatial oligopolistic equilibrium is restored. Furthermore, due to some residual monopolistic power, prices do not converge to the perfectly competitive equilibrium prices when the distance between the firms shrinks to zero. In conclusion the model exhibits a fundamental difference in the market structure, when the spatial aspect is incorporated.     

Natural oligopolies with exogenous sunk costs: A non-Suttonian result

In a spatial competition model with exogenous fixed costs and divisible goods, we obtain non-Suttonian results. When the economy is infinitely replicated, the number of firms does go to infinity but, as consumers’ income goes to infinity, the equilibrium number of firms tends toward a finite value. This occurs because the global demand to each firm becomes in the limit infinitely sensitive to price differentials since they give then rise to infinitely large differences in purchase expenditure.     

Capacity sharing with different oligopolistic competition and government regulation in a supply chain

This paper constructs a capacity sharing model in a supply chain to reveal the factors affecting equilibrium outcomes. The results show that improving the technical level lowers capacity charge and increases seller profits in any case. Product differentiation has uncertain impacts on equilibrium outcomes, which depend on government regulations and oligopolistic competition models. The improvement of supplier's fixed component of marginal costs improves capacity sharing charge and reduces profits and consumer surplus. The government regulations and oligopolistic competition model directly affect equilibrium outcomes and welfare distribution. Government capacity control helps improve social welfare, but the effect of government subsidies is uncertain.     

Local public goods, property values, and local public choice

This paper examines the relationship between the benefits and costs of local public good provision and local property values within the context of the Koopmans-Beckmann-Gale location-assignment model. Property values do not in general measure accurately the marginal net benefits of local public goods; special conditions sufficient for property values to measure or bound the marginal net benefits are stated, however. In addition, it is shown that under certain circumstances, households vote for property-value-enhancing levels of local expenditures. Under these conditions, a political equilibrium produces a Lindahl solution to the local public good problem.     

The commuting time paradox

We examine the conditions for the ‘commuting time paradox’ which states that the average commuting time does not vary between different periods. We develop therefore an equilibrium job search model with endogenously chosen commuting costs. Presuming wage bargaining between workers and firms, the optimally chosen maximum commuting costs jointly maximise the worker's and firm's payoffs. We demonstrate that when productivity levels increase over time, average commuting costs and average wages both increase, which affects the optimally chosen commuting time. We establish the conditions under which the paradox holds.     

城市扩展的两个均衡条件及其政策含义

论文认为中国的快速城市化侵占了大量的耕地,是迫使粮食在质量差的土地上生产的重要因素之一,造成了巨大的外部成本,应将其整合到城市扩展的代价中,以提高农业对土地的竞争性,求得城乡之间良好平衡.在这个基础上,还应在市区改造和新区建设之间取得平衡,即边缘地块上地租的净增加值应相等.收取的外部费用要用于土地的农业生产外部不经济性治理.土地管理应城乡整合,包括都市更新与新区建设通盘考虑.论文的研究等价于说,如果做到了如上所迷,那么城市扩展导致的土地价值上升部分就能够覆盖它的社会代价:基础设施建设的投入、拆迁投入、土地生产力建设投入和消除土地的农业生产外部不经济性投入.城市发展用地和农业用地会处在一个比较公平的竞争环境中,取得良好的平衡.     

Dumping, adjustment costs and uncertainty

Domestic demand uncertainty in the presence of adjustment costs can cause profit-maximizing firms to sell output abroad at a loss. Firms may dump output at prices below long-run marginal and average productions costs with probability arbitrarily close to one. The model predicts dumping is particularly likely in process industries such as steel. Closed form dumping solutions and interesting comparative statics are obtained. Also, the effect of domestic competition on dumping is examined. I find domestic competition increases total dumping, although a monopolist maximizing output subject to a zero expected profit constraint will dump more than a competitive industry.     

A behavioural model of traffic congestion: Endogenizing speed choice, traffic safety and time losses

Conventional economic models of traffic congestion assume that the relation between traffic flow and speed is a technical one. This paper develops a behavioural model of traffic congestion, in which drivers optimize their speeds by trading off time costs, expected accident costs and fuel costs. Since the presence of other drivers affects the latter two cost components and hence the Nash equilibrium speed, a ‘behavioural’ speed-flow relationship results for which external congestion costs include expected accident costs and fuel costs, in addition to the time costs considered in the conventional model. It is demonstrated that the latter in fact even cancel in the calculation of optimal congestion tolls. The overall welfare optimum in our model is found to be off the speed-flow function, and off the average and marginal cost functions derived from it in the conventional approach. This full optimum requires tolls to be either accompanied by speed policies, or to be set as a function of speed. Using an empirically calibrated numerical simulation model, we illustrate these qualitative findings, and attempt to assess their potential empirical relevance.     

Learning by fund-raising

From experience, fund-raisers become more efficient solicitors. This paper offers a full characterization of the optimal solicitation strategy when there are learning economies. The characterization is recursive, and does not require equilibrium computations. Our main results are that (1) the fund-raiser may now solicit a “ net free-rider”—a donor whose contribution falls below the marginal solicitation cost; (2) the number of solicitations is non-monotonic in the learning rate; and (3) a solicitation technology with high overhead but low marginal costs is likely to be optimal if income distribution in the population is relatively homogenous. The complementary case with a decreasing returns to scale technology is also considered.     

Price Dispersion and Consumer Reservation Prices

We describe firm pricing when consumers follow simple reservation price rules. In stark contrast to other models in the literature, this approach yields price dispersion in pure strategies even when firms have the same marginal costs. At the equilibrium, lower price firms earn higher profits. The range of price dispersion increases with the number of firms: the highest price is the monopoly price, while the lowest price tends to marginal cost. The average transaction price remains substantially above marginal cost even with many firms. The equilibrium pricing pattern is the same when prices are chosen sequentially.     

Oligopoly firms with quantity-price strategic decisions

An agent-based model is used to determine market equilibrium with price-setting firms in an oligopoly market. The agent-based model is designed to match the experimental rules that Brandts and Guillen (J Ind Econ 55:453–474, 2007) used with human subjects. Their model uses posted prices and advance production of a perishable good. When the marginal cost is zero, the analytical Bertrand solution is almost perfect competition. When the marginal cost is nonzero, the game does not have a theoretical equilibrium in pure strategies. The agent-based model results show that with one or two firms, prices are at or near the monopoly level, which matches the human experiments. With four firms, prices are always at the perfectly competitive level when particle swarm optimization is used. Results using a genetic algorithm, however, are noisier than those using the particle swarm optimization, and the genetic algorithm falls short of the competitive solution. The triopoly market changes from mostly monopoly to a price in between monopoly and perfect competition when a marginal cost is added. The computerized agents tend to overproduce so that profits are negative in the three- and four-firm cases when production is costly. While the prices in the simulation are close to those observed in experiments with human subjects, the inefficiency due to overproduction is much greater in the agent-based model results. This result suggests that human agents are able to reach solutions, perhaps through social norms, that are missed by the simple agent-based rules used here.     

Frequency competition and environmental costs: An application to European air transport liberalization

In this paper, we analyze symmetric frequency equilibria in airline markets; these equilibria are derived as multiproduct oligopoly solutions in a spatial competition model. Competitive equilibria are compared with a regulated equilibrium; in order to assess the welfare implications of European air transport liberalization, we compute numerical solutions using data for 21 regulated European interstate routes in 1990. We conclude that, following the introduction of competition in these markets, consumer welfare is significantly higher due to frequency increases and fare decreases. Profits decrease and, as a result of higher departure frequencies, environmental costs increase. However, the gains in consumer welfare more than compensate the decrease in profits and the rise in environmental costs.     

Urban search models under high-relocation costs. Theory and application to spatial mismatch

We develop a search-matching model in which mobility costs are so high that it is too costly for workers to relocate when a change in their employment status occurs. We show that, in equilibrium, wages increase with distance to jobs and commuting costs because firms need to compensate the transportation cost difference between the employed and unemployed workers at each location in the city. We also show that the equilibrium land rent is negatively affected by the unemployment benefit because an increase in the latter induce firms to create less jobs, which, in turn, reduces the competition in the land market. We then use this model to provide a mechanism for the observed spatial mismatch between where black workers live and where jobs are. We finally show that a transportation policy consisting in subsidizing the commuting costs of black workers can increase job creation and reduce unemployment if the level of the subsidy is set at a sufficiently high level.     

Existence of equilibrium configurations of competitive firms on an infinite two-dimensional space

This paper analytically examines the existence of equilibrium configurations of competitive firms on an infinite two-dimensional space. It is shown that the Löschian configuration (a regular-hexagonal lattice) and a square lattice are in global equilibrium; the Löschian configuration is in the strongest global equilibrium among the regular lattices (in this sense, spatial competition leads to the social optimum); and the so-called back-to-back configuration is not in equilibrium. These results are in marked contrast to those obtained from a one-dimensional model, implying that spatial equilibrium configurations in a two-dimensional space should not be inferred only from one-dimensional models frequently employed in spatial economics.     

Transaction costs and a redundant security: divergence of individual and social relevance

This paper shows that, in markets with transaction costs, even if a redundant security does not even save individual investors' total costs for their security trading, the prices of the other securities may well be different were it to not be available for trade, resulting in a different equilibrium consumption allocation. In this sense, a redundant security may give rise to the divergence of individual and social relevance in markets with transaction costs. We then show that this divergence may also be a robust phenomenon with respect to perturbations in utility functions, initial endowments, and transaction costs.