INTERNATIONAL TRADE AND COURNOT EQUILIBRIUM: EXISTENCE,UNIQUENESS AND COMPARATIVE STATICS *

This paper proves the existence and uniqueness of Cournot equilibrium in models of international trade under oligopoly. The existence of Cournot equilibrium is established without the usual assumption that profit functions are concave. Instead the proof uses a weaker‘aggregate concavity’condition. A simple proof is used to establish the uniqueness of the equilibrium. And, the paper considers the implications of the assumptions, used to prove the existence and uniqueness of the equilibrium, on the comparative static results.     

UNIQUENESS AND INDETERMINACY OF THE EQUILIBRIUM GROWTH PATH IN THE UZAWA‐LUCAS MODEL WITH SECTOR SPECIFIC EXTERNALITIES*

We introduce sector specific external effects of human capital on production in an otherwise Uzawa‐Lucas model of endogenous growth; and show that the problem of indeterminacy of the competitive equilibrium growth path does not exist even if the production function satisfies the increasing returns to scale at the social level.     

THE EXISTENCE OF EQUILIBRIUM IN A DIFFERENTIATED DUOPOLY WITH NETWORK EXTERNALITIES*

The existence of a pure‐strategy subgame‐perfect equilibrium in qualities and prices is investigated in a duopoly model of vertical differentiation where quality improvements require a quadratic variable cost and network externalities operate. We show that there exists a parameter region where the incentive to predate at the quality stage prevents firms from reaching a pure‐strategy non‐cooperative equilibrium with prices above marginal costs. If network externalities are sufficiently large, a Bertrand equilibrium with zero profits may arise, although the amount of product differentiation is strictly positive.     

AN EQUILIBRIUM SEARCH MODEL OF SYNCHRONIZED SALES*

We demonstrate the existence of periodic nonstationary equilibria with self‐generating cycles in a simple model of random search. Our results provide a theory of synchronized sales based on product market search by heterogeneous consumers. That is, our model explains how it can be optimal for all sellers to follow a repeated pattern of posting a high price for several periods and then posting a low price for one period.     

UNIQUENESS OF EQUILIBRIUM PAYOFFS IN FINITELY REPEATED GAMES WITH IMPERFECT MONITORING*

This paper examines when a finitely repeated game with imperfect monitoring has a unique equilibrium payoff vector. This problem is nontrivial under imperfect monitoring, because uniqueness of equilibrium (outcome) in the stage game does not extend to finitely repeated games. A (correlated) equilibrium is equilibrium minimaxing if any player's equilibrium payoff is her minimax value when the other players choose a correlated action profile from the actions played in the equilibrium. The uniqueness result holds if all stage game correlated equilibria are equilibrium minimaxing and have the same payoffs. The uniqueness result does not hold under weaker conditions.     

EXISTENCE AND UNIQUENESS OF AVERAGE COST PRICING EQUILIBRIA: A DEGREE THEORETIC APPROACH

This paper considers the issues of existence and uniqueness of average cost pricing equilibria within the context of a single, regulated, multiproduct monopoly with additively separable costs. We employ basic degree theoretic arguments to establish conditions under which an average cost pricing equilibrium exists. The degree theoretic approach permits the development of uniqueness results in a very natural manner.     

EQUILIBRIUM AND THE CORE IN ALONSO'S DISCRETE POPULATION MODEL OF LAND USE*

Conventional wisdom tells us that with no market failure and local nonsatiation of preferences, the core is at least as large as the collection of competitive equilibrium allocations. We confirm this for a standard model featuring private ownership of land. Next we consider the public land ownership version of the model. If the role of land ownership and rent distribution is assumed by a government that ploughs back rent (at least in excess of its agricultural value) to its citizens, the equilibrium allocation remains efficient, but no longer need be in the core.     

EXISTENCE OF STATIONARY EQUILIBRIUM IN AN INCOMPLETE-MARKET MODEL WITH ENDOGENOUS LABOR SUPPLY

In this article, I first study an income fluctuation problem with endogenous labor supply. Let β be the agent's time discount factor and be the constant gross rate of return on assets. For , I show that the agent's wealth either approaches infinity almost surely or converges to a finite level almost surely. For , I prove the existence, uniqueness, and stability of the stationary distribution of state variables. I then show the existence of the stationary general equilibrium in an incomplete-market model with endogenous labor supply.     

SOCIAL INTERACTIONS AND THE DEMAND FOR SPORT: AN ECONOMIC ANALYSIS

This paper explores the decision to participate in sports activities in the United Kingdom and the subsequent frequency of participation. The paper draws links between economic and other theories of social interaction to motivate the discussion and links these theories to assessing policy initiatives in the United Kingdom. Cluster analysis is combined with a Heckman analysis to examine the empirical evidence provided by the General Household Survey in 2002. The results suggest that social and personal capital are of paramount importance in determining sports participation, and consequently, it is these features that policy should focus upon. However, the legitimacy of policy activism requires philosophical justification. ( JEL B41, C2, D11, D12)     

A MODEL OF BUREAUCRACY AND CORRUPTION*

We analyze bureaucracy and corruption in a market with decentralized exchange and “lemons.” Exchange is modeled as a sequence of bilateral, random matches. Agents have private information about the quality of goods they produce and can supplement trade with socially inefficient bribes. Bureaucracy is modeled as a group of agents who enjoy centralized production and consumption. Transaction patterns between the bureaucracy and the private sector are fully endogenous. Centralized production and consumption in the bureaucracy give rise to low power incentives for the individual bureaucrats. As a result, private agents might bribe bureaucrats, whereas they do not bribe each other. An equilibrium with corruption and an equilibrium without corruption can coexist. We discuss some welfare implications of the model.     

AN ESTIMABLE DYNAMIC GENERAL EQUILIBRIUM MODEL OF WORK,SCHOOLING, AND OCCUPATIONAL CHOICE*

This article develops and estimates a dynamic general equilibrium overlapping‐generations model of career decisions. The model is fit to data on life cycle employment, schooling, and occupation decisions and on life cycle labor earnings, within and between cohorts observed in the United States between 1968 and 1993. Based on the estimates of the model, the impact of cohort size on skill prices and the general equilibrium effect of a tuition subsidy are assessed.     

COMPETITIVE GROWTH IN A LIFE‐CYCLE MODEL: EXISTENCE AND DYNAMICS*

The dynamic behavior of the capital growth rate is analyzed using an overlapping‐generations model with continuous trading. Assuming a technology satisfying constant social returns to capital, the equilibrium growth rate is piecewise‐defined by functional differential equations with both delayed and advanced terms. The main result concerns the existence of a solution expressed as a series of exponentials, which is shown to crucially depend on the initial wealth distribution among cohorts. Upon existence, the dynamics of the capital growth rate has a saddle‐point trajectory that converges to a unique steady state. Along the transition path, the growth rate exhibits exponentially decreasing oscillations.     

STABILITY AND INSTABILITY OF THE COUCRNOT EQUILIBRIUM*

Conditions for the Cournot equilibrium to be locally asymptotically stable or unstable are explored, which are still compatible with the second‐order condition for the optimum. The Cournot equilibrium may not be stable even if the condition owing to Fisher (1961 ), Hahn (1962 ), and Okuguchi (1964 , 1976, 1999 ) is satisfied, which was given as a sufficient condition for the Cournot equilibrium to be stable. However, as long as a game by symmetric players is concerned, the Cournot equilibrium is unstable whenever F‐H‐O condition is not satisfied. In this sense, that F‐H‐O condition is not satisfied is sufficient for the Cournot equilibrium to be unstable.     

AN EMPIRICAL STATIONARY EQUILIBRIUM SEARCH MODEL OF THE HOUSING MARKET*

This article specifies and estimates a computationally tractable stationary equilibrium model of the housing market. The model is rich and incorporates many of its unique features: buyers’ and sellers’ simultaneous search behavior, heterogeneity in their motivation to trade, transaction costs, a trading mechanism with posting prices and bargaining, and the availability of an exogenous advertising technology that induces endogenous matching. Estimation uses Maximum Likelihood methods and Multiple Listing Services data. The estimated model is used to simulate housing market outcomes when (a) the amount of information displayed on housing listings increases and (b) real estate agent’s commission rates change.     

A POSITIVE THEORY OF GEOGRAPHIC MOBILITY AND SOCIAL INSURANCE*

This article presents a tractable dynamic general equilibrium model explaining cross‐country data on geographical mobility, unemployment, and labor market institutions. Rational forward‐looking agents vote on unemployment insurance (UI). Agents with higher moving costs (larger attachment to their location) prefer more generous UI. Attachment is assumed to increase with the duration of residence. UI mitigates incentives for moving and increases, therefore, the fraction of attached agents and the political support for UI. This self‐reinforcing mechanism can yield two steady‐states: one “European” and one “American.” The former (latter) features high (low) unemployment, low (high) geographical mobility, and high (low) UI.     

INCENTIVES AND THE COST OF FIRING IN AN EQUILIBRIUM LABOR MARKET MODEL WITH ENDOGENOUS LAYOFFS*

I study the effects of firing costs in an equilibrium model of the labor market with moral hazard. Layoff is an incentive device, modeled as termination of the optimal long‐term contract. When the economy’s stock of firms is fixed, firing costs could reduce layoffs and increase worker welfare. In the long run when firms are free to enter and exit the market, firing costs generate not only lower employment, longer unemployment durations, and lower aggregate output, but also lower welfare for both employed workers and new labor market entrants.     

BUSINESS CYCLES IN THE EQUILIBRIUM MODEL OF LABOR MARKET SEARCH AND SELF‐INSURANCE*

I introduce risk‐aversion, labor‐leisure choice, capital, individual productivity shocks, and market incompleteness to the standard model of labor search and matching and investigate the model’s cyclical properties. I find that the model can generate the observed large volatility of unemployment and vacancies with a reasonable replacement rate of unemployment insurance benefits of 64%. Labor‐leisure choice plays a crucial role through additional utility from leisure when unemployed and further amplification from adjustments of hours worked. On the other hand, the borrowing constraint or individual productivity shocks do not significantly affect the cyclical properties of unemployment and vacancies.