Existence of equilibria based on continuity and boundary behaviour

This paper establishes an existence result of price equilibria for excess demand functions which makes exclusive use of the continuity of these functions and of a boundary condition. Degree theory is shown to be a natural tool for proving such a result.     

Rationalizable variable-population choice functions

Summary. We analyze the rationalizability of variable-population social-choice functions in a welfarist framework. It is shown that fixed-population rationalizability and a weakening of congruence together are necessary and sufficient for rational choice, given a plausible dominance property that prevents the choice of alternatives involving low utility levels. In addition, a class of critical-level separable choice functions is characterized. This result, which extends an earlier axiomatization of a related class of bargaining solutions to a variable-population setting, is the first axiomatization of critical-level principles in a general choice-theoretic model. Received: November 30, 1999; revised version: September 11, 2000     

Product R&D Investment Policies in an International Duopoly

This study analyzes the optimal product R&D investment policies of a developed and a developing country in an international Cournot duopoly where firms from these two countries compete through endogenous quality–quantity decisions. We explore a new international trade model by using demand functions derived from utility functions. We find that the optimal product R&D investment policies for both countries are subsidies. This study counters a finding that used Hotelling‐type demand functions and it partially modifies another result that adopted the same demand functions but with an international Bertrand duopoly.     

Non-computability of competitive equilibrium

Summary. We provide a “computable counterexample” to the Arrow-Debreu competitive equilibrium existence theorem [2]. In particular, we find an exchange economy in which all components are (Turing) computable, but in which no competitive equilibrium is computable. This result can be interpreted as an impossibility result in both computability-bounded rationality (cf. Binmore [5], Richter and Wong [35]) and computational economics (cf. Scarf [39]). To prove the theorem, we establish a “computable counterexample” to Brouwer's Fixed Point Theorem (similar to Orevkov [32]) and a computable analogue of a characterization of excess demand functions (cf. Mas-Colell [26], Geanakoplos [16], Wong [50]). Received: September 9, 1997; revised version: December 17, 1997     

Diversification of interdependent prospects

This paper extends the stochastic dominance approach to the problem of diversification of interdependent prospects. One basic result is that a risk averter should always mix any two identically distributed prospects, regardless of the nature of the interdependence between them. A similar result holds for the case of n prospects, provided all the joint distribution functions of dimension n ? 1 are identical. When the n-dimensional joint distribution function is symmetric, then the optimal strategy is to put an equal amount into each prospect. The paper also provides conditions which make diversification optimal in the absence of identical marginal distributions.     

Time consistency and optimal government policies in perfect foresight equilibrium

This paper develops a framework for determining optimal monetary and fiscal policies in perfect foresight equilibrium. Such equilibria have the property that all underlying demand and supply functions are derived from optimizing behavior, expectations are realized, and all markets clear. The time consistency of optimal policies derived under such circumstances is analyzed for a variety of alternative optimal policy problems. The general conclusion is that time consistency will prevail with respect to the optimization of any single policy instrument which does not appear explicitly in the indirect utility functions; otherwise time inconsistency will result. Monetary instruments are generally examples of the former, and fiscal instruments examples of the latter.     

An efficiency theorem for incompletely known preferences

There are n agents who have von Neumann-Morgenstern utility functions on a finite set of alternatives A. Each agent i's utility function is known to lie in the nonempty, convex, relatively open set Ui. Suppose L is a lottery on A that is undominated, meaning that there is no other lottery that is guaranteed to Pareto dominate L no matter what the true utility functions are. Then, there exist utility functions ui∈Ui for which L is Pareto efficient. This result includes the ordinal efficiency welfare theorem as a special case.     

The relevance of input substitution in the inter-industry model

Using 17 annual input-output tables of the Maltese economy, this study examines the effect of input prices on input-output coefficients. The Leontief production function is substituted by the generalised Leontief cost function and input demand functions are derived. The empirical result that 56 percent of these derived input demand functions have a relative price variable which is significant indicates that, in general, the Leontief specification is rejected in favour of the generalised Leontief form used in this study. This result, along with a marked improvement in forecasting ability, suggests that this modification of the traditional Leontief specification is worthwhile.     

Kreps & Scheinkman with Product Differentiation

Kreps and Scheinkman (1983)’s celebrated result is that in a two-stage model of a market with homogeneous products in which firms noncooperatively pick capacities in the first stage and set prices in the second stage, the equilibrium outcome is that of a one-shot Cournot game. This note derives capacity best response functions for the first stage and extends the Kreps and Scheinkman result to the case of differentiated products.     

Exponential functionals of integrated processes

This paper derives a limit distribution result involving exponential functionals of integrated processes. This implies the availability of an additional class of functions for which the limit behavior of the average of a function of an integrated process is well-established.     

On Elimination in Contests: A Perspective on Output Maximization

This paper investigates the desirability of adding a preliminary elimination stage for output maximization in a winner‐take‐all contest framework in which the contestant who achieves the highest (random) output wins. We find that, generally, the desirability of an elimination stage does not monotonically depend on the productivity of the effort; adding a preliminary stage can improve output for both concave and convex production functions. This result contrasts sharply with current insight from effort maximization, which argues that adding a preliminary stage can increase effort supply only if the production function is concave.     

政府推进循环经济发展的职能研究

发展循环经济是政府的必然选择和迫切任务,探讨政府推进循环经济发展的职能有着十分重要的意义。本文从循环经济运行结果的外部性和运行条件的规模性两个方面分析了政府推进循环经济发展的必要性,由此分析了政府在推进循环经济发展过程主要承担制度建立和条件保证两大类职能及其具体内容。     

A KKM-result and an application for binary and non-binary choice functions

Summary. By generalizing the classical Knaster-Kuratowski-Mazurkiewicz Theorem, we obtain a result that provides sufficient conditions to ensure the non-emptiness of several kinds of choice functions. This result generalizes well-known results on the existence of maximal elements for binary relations (Bergstrom [4]; Walker [16]; Tian [15]), on the non-emptiness of non-binary choice functions (Nehring [12]; Llinares and Sánchez [9]) and on the non-emptiness of some classical solutions for tournaments (top cycle and uncovered set) on non-finite sets. Received: December 29, 1999; revised version: October 18, 2001     

On the existence of optimal processes in non-stationary environments

We consider an aggregative model of intertemporal allocation under uncertainty, in which the utility and production functions are allowed to be time dependent, the random shocks occurring in each period are entirely arbitrary, and the production functions are permitted to be non-concave. In this framework, we provide a theorem on the existence of infinite-horizon optimal processes. In the course of establishing this result, we obtain the existence of optimal policy functions and we show that they are monotone in the stock levels.This paper has benefitted from the comments of two referees of the journal. Research of the first author was supported by a National Science Foundation Grant.     

Ex ante efficiency implies incentive compatibility

We show that when agents become informationally negligible in a large economy with asymmetric information, every ex ante efficient allocation must be incentive compatible. This means that any ex ante core or Walrasian allocation is incentive compatible. The corresponding result is false for fixed finite-agent economies with asymmetric information. An example is also constructed to show that the ex post version of the result does not hold. Furthermore, we show that the result is sharp in the sense that it will fail to hold if one relaxes any of the main assumptions, namely, strong conditional independence on the information structure, strict concavity on the utility functions, type independence on the utility functions and endowments.      

World oil: the growing case for international policy

Can the economic theory of depletion be reconciled with low petroleum prices? This article uses a revision of the theory, which reflects demand functions that rise in response to increasing world population and income. The magnitude of producers' and consumers' surplus is estimated under both competitive and monopolistic assumptions; the result indicates a present value comparable to or in excess of today's gross world economic product. Game theory suggests a framework that explains the interaction between oil pricing and military policy, and the economic incentives that result in a general pattern of recent market equilibrium crude oil prices often fluctuating with a $15–20 per barrel range. The analysis concludes that the economic incentives for political instability in the Persian Gulf will increase, and more formal methods of setting the international framework for Persian Gulf oil may be expected.     

Can We Meaningfully Speak of Changes in Price under the Regime of Changes in Techniques?

Abstract

This paper presents a simulation exercise on Sraffa's system under various types of technical changes to show that the direction of changes in prices of commodities is contingent on the choice of the numeraire. Thus, such a comparison of prices in two systems turns out to be meaningless. This result points to the arbitrary nature of the neoclassical supply functions, as they inevitably compare prices across several Sraffa systems on the basis of an arbitrarily chosen numeraire. We anticipated such a result from our reading of Sraffa as part of his ‘prelude to a critique of economic theory’.     

KALDORIAN DEMAND FUNCTIONS AND THE RETURN TO CAPITAL: AN ANALYSIS IN A TRADE THEORETIC FRAMEWORK

Abstract.  This paper shows that under certain plausible conditions capital accumulation raises the return to capital. A three good trade theoretic model with Kaldorian demand functions is used to establish this result. This proposition is also independent of the assumption of diminishing return to capital a key feature of endogenous growth theory. Our result sheds light on the high rates of investment and growth that many East Asian economies have achieved.     

Non-parametric test of time consistency: Present bias and future bias

This paper reports the elicited time preference of human subjects in a laboratory setting. The model allows for non-linear utility functions, non-separability between delay and reward, and time inconsistency including future bias in addition to present bias. In particular, the experiment (1) runs a non-parametric test of time consistency and (2) estimates the form of time discount function independently of instantaneous utility functions, and then (3) the result suggests that many subjects exhibiting future bias, indicating an inverse S-curve time discount function.     

Global convergence of adaptive learning in models of pure exchange

Summary. This paper develops an adaptive learning scheme for a standard version of the OLG model with pure exchange. Perfect forecasting rules which generate perfect foresight orbits are approximated by cubic spline functions. These approximations are successively constructed using historical data only. Trajectories generated by this scheme converge to perfect foresight orbits globally for all initial conditions. This result holds for all parameterizations guaranteeing the existence of a monetary steady state and hence is independent of consumers' savings behavior. It generalizes to all one-dimensional models of the Cobweb type. Received: October 5, 2000; revised version: February 15, 2001