THE CASE FOR PAY-AS-YOU-GO PENSIONS IN A SERVICE ECONOMY

The elderly consume more labour‐intensive services than young individuals. This makes them vulnerable to rising costs of services due to higher wages, which can be caused by increased capital accumulation. This paper shows that in a model with a service sector, the golden‐rule capital stock is lower and dynamic inefficiency is more likely to occur than in the conventional one‐sector model. This implies that in many cases, a positive Pay‐As‐You‐Go tax maximises long‐run welfare in a service economy. Calculations based on data from the United Kingdom and the Netherlands show that the long‐run optimal degree of funding coincides with the current situation in these countries.     

Stochastic stability in networks with decay

This paper considers a stylized model of network formation in which relations among agents are subject to frictions, as described in Bala and Goyal [A non cooperative model of network formation, Econometrica 68 (2000) 1181-1231]. We analyze the process of network formation in a dynamic framework where self-interested individuals can form or delete links and, occasionally, make mistakes. Then, using stochastic stability, we identify the network structures to which the formation process will converge.     

The role of boundary solutions in principal-agent problems of the Holmström-Milgrom type

The paper extends the Holmström-Milgrom [B. Holmström, P. Milgrom, Aggregation and linearity in the provision of intertemporal incentives, Econometrica 55 (1987) 303-328] analysis of intertemporal incentive provision to allow for the implementation of actions on the boundary of the feasible set. Boundary actions provide the principal with some freedom in choosing incentive schemes. This can be used to reduce premia. The paper characterizes optimal incentive schemes for the continuous-time Brownian-motion model and its discrete-time approximations. Linearity of incentive schemes in “accounts” is confirmed. However, for models with effort costs depending only on mean returns, the availability of boundary actions destroys the linearity of optimal incentive schemes in profits.     

Quality dualism

We suggest a theory of quality dualism, defined in terms of the gap between the highest quality good produced in the informal sector and the lowest quality produced in the formal sector. We develop a model of vertically differentiated products, in which firms producing in the formal and informal sectors face different factor prices, and have a relative advantage in the manufacture of different qualities. We then use the model to examine the cyclical behavior of the respective sizes of the two sectors. Finally, we point out that factor price changes, which reduce or increase the size of the informal sector, may have the same or opposite effect on the degree of dualism in the economy.     

R&D competition, absorptive capacity, and market shares

This paper deals with an oligopolistic industry where firms are engaged in cost-reducting R&D activity to maximize their market shares. The existence and uniqueness of a feedback-Nash-optimal R&D strategy for each firm are discussed. Our simulations highlight that variations in spillovers hardly influence the firms' R&D investment, if their absorptive capacities to exploit extramural knowledge depend on their R&D efforts. Moreover, extramural knowledge cannot completely replace in-house R&D. However, a high level of public R&D favors the firm with the most restrictive R&D expenditure constraint and/or with the lowest initial R&D stock, provided it invests in R&D.     

Entry restrictions and the determination of quality

Entry restrictions are a common form of regulation in markets and occupations, either as a means of limiting the size of a market or affecting the quality of products or services provided by it. This paper analyzes demand, cost and informational characteristics that affect the impact of this type of policies on the quality mix of products provided by an industry and the welfare of its consumers. Selective increases in the costs of entry such as licensing requirements and direct restrictions with competitive bidding for entry rights are considered. We analyze the effects of these policies on entry decisions and also the additional selection effects that are obtained when exit is allowed for and the rights to participate in an industry can be freely traded.     

三维GIS在“数字长沙”中的应用实例

文章就三维GIS在“数字长沙”中的应用进行了探讨,阐述了利用三维GIS为长沙市政府区域建立三维全信息模型的结构、主要功能及应用。     

Competitive behavior in market games: Evidence and theory

We explore whether competitive outcomes arise in an experimental implementation of a market game, introduced by Shubik (1973) [21]. Market games obtain Pareto inferior (strict) Nash equilibria, in which some or possibly all markets are closed. We find that subjects do not coordinate on autarkic Nash equilibria, but favor more efficient Nash equilibria in which all markets are open. As the number of subjects participating in the market game increases, the Nash equilibrium they achieve approximates the associated competitive equilibrium of the underlying economy. Motivated by these findings, we provide a theoretical argument for why evolutionary forces can lead to competitive outcomes in market games.     

The case for multi-unit single-run descending-price auctions

We show that a multiple-unit descending-price auction in which the clock is not reset after each sale may be faster and yield more stable prices than an efficient alternative, thus providing sellers a rationale for using it in practice.     

Income distribution, efficiency and rationing

This paper studies the impacts of income distribution on the efficiency of trade mechanism and rationing of agents who are priced out of trade in a dynamic search model with two-sided asymmetric information. Buyers and sellers have asymmetric information about valuations and incomes respectively. In such a frictional environment, the effects of several variants of changes in income distribution on efficiency of trading mechanism and the population of rationed buyers and sellers are elaborated.