Quasiconcavity and the kernel of a separable utility

Summary. In this paper I prove that a quasiconcave separable utility function defined on an atomless space is concave. Received: August 11, 1997; revised version: October 2, 1997     

On optimal cycles in dynamic programming models with convex return function

Summary. In this paper we study the behavior of optimal paths in dynamic programming models with a strictly convex return function. Such a model has been investigated in Dawid and Kopel (1997) who assume that the growth of a renewable resource is governed by a piecewise linear function. We prove that in their model the optimal cycles undergo the following qualitative changes or bifurcations: a cycle of period n“bifurcates” into a cycle of period n+1 for increasing elasticity of the return function. We also show that under the assumption of a concave differentiable growth function the qualitative properties of the optimal policy remain valid: oscillating behavior is optimal. Furthermore, we demonstrate numerically that the period of a cyclic optimal path increases if the convexity of the return function (measured by the elasticity) increases. Received: January 22, 1997; revised version: October 13, 1997     

Unawareness and bankruptcy: A general equilibrium model

Summary. We present a consistent pure-exchange general equilibrium model where agents may not be able to foresee all possible future contingencies. In this context, even with nominal assets and complete asset markets, an equilibrium may not exist without appropriate assumptions. Specific examples are provided. An existence result is proved under the main assumption that there are sufficiently many states that all the agents foresee. An intrinsic feature of the model is bankruptcy, which agents may involuntarily experience in the unforeseen states. Received: April 23, 1997; revised version: May 19, 1997     

Fiscal rules of income transformation

Summary. The purpose of this paper is to characterize the class of fiscal rules of income transformation which are equity improving and, at the same time, preserve the ranking of existing distributions. Contrary to the related literature individual well-being depends not just on income but also on prices. We show that, when the environment is restricted such that a general transformation class still can be defined, the only “desirable” fiscal rule is the simple redistributive linear taxation schedule, of the same type that is the rule in practice in most economies. Received: May 8, 1997; revised version: September 15, 1997     

More on subsidizing cooperative and noncooperative R&D in duopoly with spillovers

In an earlier article in this journal I compared two R&D-stimulating policies: allowing for R&D cooperatives and providing direct R&D subsidies (see Hinloopen, 1997:Journal of Economics 66: 151–175). I also considered the implementation of both policies simultaneously. Since then Amir (1998: Discussion Paper 1/1998, Odense University) has shown that the model I used as a starting point (i.e., that of d'Aspremont and Jacquemin, 1988:American Economic Review 78: 1133–1137) is not well-defined with respect to a crucial parameter (the technological spillover) and subsequently proposes an augmentation of the model. Replicating then my original analysis with this augmented model reveals that all results stated before remain valid. In addition I correct a minor error in Hinloopen (1997) related to the comparison of optimal R&D subsidies.     

The last word on Giffen goods?

Summary. Giffen goods have long been a minor embarrassment to economics. While it is customary to dismiss them as empirically irrelevant, this essay argues that a more fundamental difficulty with Giffen goods has somehow been overlooked. Received: March 20, 1996; revised version: February 3, 1997     

Expression of Concern

The Editors have been contacted regarding some concerns that the following article from Pacific Economic Review, ‘Dualism in Job Stability of the Korean Labour Market: The Impact of the 1997 Financial Crisis’ by Joonmo Cho and Jaeho Keum, published online on April 21, 2009 in Wiley Online Library (wileyonlinelibrary.com), contains unattributed overlap with the Korean‐language paper ‘A Study on Dynamic Changes in Job Stability’ by Jaeho Keum Joonmo Cho in the Korean journal Kukje Kyungje Yongu (2005, 11(3), 79–114). The Editors are aware that the Research Ethics Committee of Sungkyunkwan University (SKKU) and the Inspection Division of Korean Labor Institute (KLI) have been informed and are currently investigating this issue. Whilst awaiting the outcome of those investigations, the Editors wish to notify readers of our concerns regarding this article. This article updates: Dualism in Job Stability of the Korean Labour Market: The Impact of the 1997 Financial Crisis     

Approximation by finite horizons of the undiscounted one-sector growth model

Summary. In this paper I give a method for finding long-run-average policies in the undiscounted economic growth problem using approximations by finite horizons. Required hypothesis is the strong interiority of T-horizon solutions. Received: March 25, 1996; revised version: July 29, 1997     

Recursive utility and preferences for information

Summary. This paper presents an axiomatic foundation for recursive utility that captures the role of the timing of resolution of uncertainty without relying on exogenously specified objective beliefs. Two main representation results are proved. In the first one, future utility enters the recursion through the type of general aggregators considered in Skiadas (1997a), and as a result the formulation is purely ordinal and free of any probabilities. In the second representation these aggregators are conditional expectations relative to subjective beliefs. A new recursive representation incorporating disappointment aversion is also suggested. The main methodological innovation of the paper derives from the fact that the basic objects of choice are taken to be pairs of state-contingent consumption plans and information filtrations, rather than the temporal (objective) lotteries of the existing literature. It is shown that this approach has the additional benefit of being directly applicable to the continuous-time version of recursive utility developed by Duffie and Epstein (1992). Received: February 18, 1997; revised version: July 18, 1997     

An additively separable representation in the Savage framework

This paper proposes necessary and sufficient conditions for an additively separable representation of preferences in the Savage framework (where the objects of choice are acts: measurable functions from an infinite set of states to a potentially finite set of consequences). A preference relation over acts is represented by the integral over the subset of the product of the state space and the consequence space which corresponds to the act, where this integral is calculated with respect to an evaluation measure on this space. The result requires neither Savage's P3 (monotonicity) nor his P4 (weak comparative probability). Nevertheless, the representation it provides is as useful as Savage's for many economic applications.     

Convergence of interest rates around the Pacific Rim

This article applies the panel data unit root tests provided by Im, Pesaran and Shin (Discussion paper, 1997) to examine the interest rate convergence of small-open Asian countries with major financial centres. With monthly data from 1988:1 to 1997:6, it was found that the nominal interest rates of these countries converge to the US rates rather than to Japan's. This finding is consistent with the view that the monetary authorities of non-Japan Asian economies pegged their exchange rates overwhelmingly to the dollar rather than the yen before the financial crisis of 1997.     

Learning buyers' valuation distribution in posted-price selling

Summary. For his proof of the existence of a general competitive equilibrium Abraham Wald assumed a strictly pseudomonotone inverse market demand function or, equivalently, that market demand satisfies the Weak Axiom of Revealed Preference. It is well known that more recent existence theorems do not need this assumption. In order to clarify its role in Wald's proof, the question of existence of an equilibrium for a modified version of the Walras-Cassel model is reduced to the solvability of a related variational inequality problem. In general, the existence of a solution to such a problem can only be proved by advanced mathematical methods. We provide an elementary induction proof which demonstrates the essence of Abraham Wald's famous contribution. Received: July 22, 1997; revised version: December 11, 1997     

Regime shifts in the Danish term structure of interest rates

Within a bivariate VAR model allowing for two-state Markov regime switching we test and evaluate the Expectations Theory (ET) of the term structure using Danish 1- and 3-months interest rates covering the period 1976–1997. A regime-shift approach is used in order to account for the change in monetary policy and the 1992–93 exchange rate crises that occured during this period. The basic findings are that these episodes did change the term structure, and, although we do find departures from the ET, several of the implications of the theory are consistent with the data, especially in the later part of the sample. First version received: June 1997/Final version received: March 1998     

Efficiency and options on the market index

Summary. In a static exchange economy, when all the endowments are issued as securities on a stock exchange, Pareto optimal allocations may be reached by trading options on the market index (see Breeden and Litzenberger (1978)). We extend this result when some of the risks cannot be exchanged on the market. Options on an appropriate index, which typically differs from the market index, depending on the correlation of the non-tradable risks with the exchanged securities, are still an appropriate tool to support a (constrained) efficient equilibrium. This suggests that the recent development of derivatives based on interest rates may be an efficient way to reach a Pareto optimal allocation of risks. Received: June 16, 1997; revised version: July 25, 1997     

A note on duality in consumer theory

Summary. In this paper we will show that upper semicontinuity of the indirect utility function implies the upper semicontinuity of the direct utility function. By strengthening the assumptions, one can also deduce the continuity of the utility function. Based on indirect utility functions a model of consumer behavior will be established. Received: December 26, 1996; revised version: August 25, 1997     

Theorems on correspondences and stability of the core

In this note two theorems strengthening Grodal's (1971) Theorem on correspondences are proved. The first drops the convexity assumption. The second strengthens that theorem further for the case when the range is the positive orthant. In this case, the conclusion of Grodal's Theorem - the intersection of the integral with the interior of the range being open- is modified to read as the integral being a relative open subset of the positive orthant. An example is provided to show that, such a strengthening is not valid in general. This allows us to dispense with the requirment of convexity of preferences in Grodal's (1971) theorems on the closedness of the set of Pareto optimal allocations, the core, and the continuity of the core correspondence for pure exchange economies. We apply this result to show that blocking coalitions in a large economy are stable. Received: September 30, 1998; revised version: September 18, 2001 RID="*" ID="*" The author is grateful to an anonymous referee for helpful comments. The usual disclaimer applies.     

Auctions with endogenous valuations: the snowball effect revisited

Summary. This paper looks at the determination of ownership of capacity when there are two ex-ante symmetric agents bidding for many units of capacity which are sold sequentially. It is shown that convexity of payoffs in the final stage of the game is sufficient to ensure monopolization of capacity, but that increasing returns to scale are not sufficient to ensure monopolization. Received: March 14, 1997; revised version: December 1, 1997     

Efficient strategy-proof allocation functions in linear production economies

Summary. In a linear production model, we characterize the class of efficient and strategy-proof allocation functions, and the class of efficient and coalition strategy-proof allocation functions. In the former class, requiring equal treatment of equals allows us to identify a unique allocation function. This function is also the unique member of the latter class which satisfies uniform treatment of uniforms. Received: July 10, 1997 / Revised version: November 24, 1997     

Manipulation-proof equilibrium in atomless economies with commodity differentiation

Summary. In this paper, we introduce a perfect competition test which checks the incentives of arbitrarily small coalitions to behave strategically in endowments and preferences. We apply this coalitional incentive compatibility test to atomless economies with a continuum of differentiated commodities. We show that, under thickness conditions, economies with a finite number of types and economies whose set of agents' preferences is compact, pass this perfect competition test. Limiting results for replica economies are also presented. Received: July 25, 1997; revised version: December 5, 1998