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.     

Egalitarianism under population change: Age structure does matter

We study the compatibility of the optimal population size concepts produced by different social welfare functions and egalitarianism meant as “equal consumption for all individuals of all generations”. Social welfare functions are parameterized by an altruism parameter generating the Benthamite and Millian criteria as polar cases. The economy considered is in continuous time and is populated by homogeneous cohorts with a given life span. Production functions are linear in labor, (costly) procreation is the unique way to transfer resources forward in time. First, we show that egalitarianism is optimal whatever the degree of altruism in “perpetual youth” model, that is when lifetime span is finite but age structure does not matter: in this case egalitarianism does not discriminate between the social welfare functions considered. Then we show that, when life span is finite but age structure matters, egalitarianism does not arise systematically as an optimal outcome. In particular, in a growing economy, that is when population growth is optimal in the long-run, this egalitarian rule can only hold when the welfare function is Benthamite. When altruism is impure, egalitarianism is impossible in the context of a growing economy. Either in the Benthamite or impure altruism cases, procreation is never optimal for small enough life spans, leading to finite time extinction and maximal consumption for all existing individuals.     

Stackelberg equilibrium with many leaders and followers. The case of zero fixed costs

I study a version of the Stackelberg game with many identical firms in which leaders and followers use a continuous cost function with no fixed cost. Using lattice theoretical methods I provide a set of conditions that guarantee that the game has an equilibrium in pure strategies. With convex costs the model shows the same properties as a quasi-competitive Cournot model. The same happens with concave costs, but only when the number of followers is small. When this number is large the leaders preempt entry. I study the comparative statics and the limit behavior of the equilibrium and I show how the main determinants of market structure interact. More competition between the leaders always displaces the followers. Instead, how a stronger threat of entry affects the equilibrium depends on the technology. With strictly convex costs it is the followers that eventually displace the leaders.     

金融创新是促进还是阻碍了经济增长——基于技术进步视角的面板分析

金融创新对经济增长的作用方向一直是不明确的,本文旨在解释清楚金融创新影响经济增长的内部机制,并对其进行验证。包括金融创新对微观技术的支持,以及进一步扩展到对宏观经济的影响。通过应用工具变量法对全球的面板数据进行处理,建立以内生经济增长理论模型为基础的计量模型进行实证研究,研究结果表明：在考虑金融创新在经济增长模型中存在内生性的情况下：与金融发展不同,金融创新单独对经济增长的作用方向是不确定的,甚至可能存在显著的抑制作用;而金融创新通过技术进步对经济增长的促进作用是显著的,并且这种作用更多地通过企业的技术进步来体现。     

Trading timing and the returns to trend-following

We document a negative impact of realistic trading timing on trend-following profits, across an international sample of equity indexes and stocks. The discount effect is substantial but reduces as trend signals become less accurate. The size of this trading timing bias is largely driven by the volatility of buy-and-hold returns and that of trend signals.     

Exogenous and Endogenous Attention and the Convergence of Analysts’ Forecasts

The propensity of the forecasts of sell-side financial analysts to converge (or diverge) is a function of their exogenous and endogenous selective attention and overconfidence. When returns are negative, the endogenous form of selective attention—a static measure of analysts’ goal-driven attention at a particular point in time—has a positive association with convergence. The exogenous form of selective attention—a relatively involuntary dynamic process of exogenous attentional shift driven by external changes in the market over time—is associated with a tendency for forecasts to diverge.     

内生农业技术进步的二元经济增长模型——对“东亚奇迹”和中国经济的再解释

通过吸收内生增长理论的思想 ,修正外生农业技术进步的假设 ,本文提出了一个内生农业技术进步的二元经济增长模型 ,并以此对倍受瞩目也颇多争议的“东亚奇迹”及中国经济 ,从二元经济结构转换的角度进行了分析。本文认为 ,“东亚奇迹”是传统农业劳动力不断转向现代非农业部门的结果 ;是现代部门以资本反哺传统部门 ,推动农业技术进步 ,促进劳动力转移的结果 ;也是现代部门均衡发展 ,吸纳剩余劳动力 ,加速结构转换的结果。因此 ,虽然非农部门的全要素生产率提高不够显著 ,但劳动力结构转换仍然推动经济实现了持久的高速增长。     

Monetising the Classical Equations: a theory of circulation

The Classical Equations describe output and income in real terms.To use them to analyse aggregate demand, the transactions theydescribe must be ‘monetised’. A sum of money equalto the wage bill of the capital goods sector can be shown tobe necessary and sufficient to carry out all transactions, ina process of circulation which also defines an expression forvelocity. When money has intrinsic value, the quantity approachmay hold in the short run but, in the long run, money will beendogenous. In these conditions, the rate of interest will bedetermined by the supply and demand for reserves, but when moneyis purely nominal, only a minimum rate will be fixed, and therate of interest will have to be pegged. The Appendix developsthe Classical Equations and shows that they define an invariableunit of account.     

Entry in contests with incomplete information: Theory and experiments

This paper studies entry decisions in contests with private values. Potential contestants observe their value and the common opportunity cost of entry, and make entry decisions simultaneously. Theory predicts that whether or not contestants are informed of the number of entrants prior to choosing their expenditures has no effect on entry or aggregate expenditures. We test these assertions in our experiments. We find substantial over-entry in both information structures. However, entry is higher when contestants are informed. Since expenditures do not, on average, differ across information structures, aggregate expenditure is also higher when contestants are informed. Contestants earn on average less than the opportunity cost of entry.     

Protection for sale under monopolistic competition: Beyond the CES

We extend the protection for sale model of Grossman and Helpman (1994) by introducing a general model of monopolistic competition with variable markups and incomplete pass-through. We show that the structure of protection emerging in the political equilibrium not only depends on the weight attached by the government to consumer welfare when making its policy decision, but also on the degree of market power of firms and on the terms-of-trade variations due to the degree of pass-through. Our results highlight the importance of preferences in shaping the structure of protection and are consistent with the occurring of protectionism also in unorganized industries.