Edgeworth's conjecture with infinitely many commodities: commodity differentiation

Summary. Convergence of the cores of finite economies to the set of Walrasian allocations as the number of agents grows has long been taken as one of the basic tests of perfect competition. The present paper examines this test in the most natural model of commodity differentiation: the commodity space is the space of nonnegative measures, endowed with the topology of weak convergence. In Anderson and Zame [12], we gave counterexamples to core convergence in L ¹, a space in which core convergence holds for replica economies and core equivalence holds for continuum economies; in addition, we gave a core convergence theorem under the assumption that traders' utility functions exhibit uniformly vanishing marginal utility at infinity. In this paper, we provide two core convergence results for the commodity differentiation model. A key technical virtue of this space is that relatively large sets (in particular, closed norm-bounded sets) are compact. This permits us to invoke a version of the Shapley-Folkman Theorem for compact subsets of an infinite-dimensional space. We show that, for sufficiently large economies in which endowments come from a norm bounded set, preferences satisfy an equidesirability condition, and either (i) preferences exhibit uniformly bounded marginal rates of substitution or (ii) endowments come from an order-bounded set, core allocations can be approximately decentralized by prices. Received: July 29, 1996; revised version: January 14, 1997     

Comparing the costs and benefits of diversification by regulated firms

Previous work on the diversification of regulated firms has focused exclusively on either the costs of cross-subsidy or on the welfare gains resulting from economies of scope. Using theory and numerical simulations, we identify conditions under which gains from economies of scope and increased competition tend to outweigh the costs of cross-subsidization. We use a perfect competition model of the unregulated market to examine tradeoffs under economies of scope. Effects of increased competition are assessed using Cournot models with linear and constant elasticity demands. Diversification tradeoffs depend upon magnitudes of variables that regulators should be able to estimate or otherwise judge.     

Environmental Taxation and Induced Structural Change in an Open Economy: The Role of Market Structure

Abstract. Studies of structural change induced by environmental taxation usually proceed in a perfect-competition framework and typically find structural change to be quite moderate under realistic emission reduction scenarios. By observing that some of the industries affected are likely to operate under imperfect rather than perfect competition, additional mechanisms emerge which may amplify structural change beyond the extent identified as yet. Especially, changes in economies of scale may arise which weaken or strengthen the competitive position of industries over and above the initial cost effect. Using a computable general equilibrium model for Germany to examine the effects of a unilaterally introduced carbon tax, we find that induced structural change is more pronounced under imperfect competition than under perfect competition. At the macroeconomic level, we find that aggregate losses in economies of scale are larger than aggregate gains, implying that the total costs of environmental regulation are higher under imperfect competition than under perfect competition.     

Convergence of the Aumann–Davis–Maschler and Geanakoplos bargaining sets

Summary. Geanakoplos [17] defined a notion of bargaining set, and proved that his bargaining set is approximately competitive in large finite transferable utility (TU) exchange economies with smooth preferences. Shapley and Shubik [26] showed that the Aumann–Davis–Maschler bargaining set is approximately competitive in replica sequences of TU exchange economies with smooth preferences. We extend Geanakoplos result to nontransferable utility (NTU) exchange economies without smooth preferences, and we extend the Shapley and Shubik result to non-replica sequences of NTU exchange economies with smooth preferences.Received: November 11, 1996This revised version was published online in February 2005 with corrections to the cover date.     

Industry equilibrium under random demand

The paper deals with the characterization of long-run industry equilibrium under random demand, for the two polar cases of perfect competition and pure monopoly. Contrary to the basic theorem of welfare economics for the standard (deterministic) case, it is shown that perfect competition does not in general lead to an optimal (efficient) outcome. Perfect competition is optimal if and only if firms display risk-neutrality with respect to profits. Surprisingly enough, when risk preferences are non-neutral, one could by means of price regulation lead monopoly to behave optimally, whereas this is impossible for competition.     

Production, trade, prices, exchange rates and equilibration in large experimental economies

We study market equilibration in laboratory economies that are larger and more complex than any that have been studied experimentally to date. Complexity is derived from the fact that the economies are “international” in economic structure with multiple input, output, and foreign exchange markets in operation. The economies have twenty-one markets and due to the fact that they have roughly fifty agents, the economies are characterized by several hundred equations. In spite of the complexity and interdependence of the economy, the results demonstrate the substantial power of the general equilibrium model of perfect competition to predict the direction of movement of market-level variables. Empirical patterns in the convergence process are explored and described.     

Uncertainty and insurance in strategic market games

Summary. For perfectly competitive economies under uncertainty, there is a well-known equivalence between a formulation with contingent goods and one with state-specific securities followed by spot markets for goods. In this paper, I examine whether this equivalence carries over to a particular form of imperfect competition. Specifically, I look at three Shapley-Shubik strategic market games: one with contingent commodities, one with Arrow securities traded under imperfect competition and one with Arrow securities traded under perfect competition. First I compare the feasibility constraints of these three games. Then I compare their equilibrium sets. As in Peck and Shell (1989), the only common equilibria between the first and the second game are those which involve no transfer of income across states. However, if the securities markets are competitive, then the set of equilibria of the contingent commodities game and the securities game coincide. Received: June 16, 1997; revised version: April 30, 1998     

Rational expectations equilibria of economies with local interactions

We consider general economies in which rational agents interact locally. The local aspect of the interactions is designed to represent in a simple abstract way social interactions, that is, socioeconomic environments in which markets do not mediate all of agents’ choices, which might be in part determined, for instance, by family, peer group, or ethnic group effects. We study static as well as dynamic infinite horizon economies; we allow for economies with incomplete information, and we consider jointly global and local interactions, to integrate e.g., global externalities and markets with peer and group effects. We provide conditions under which such economies have rational expectations equilibria. We illustrate the effects of local interactions when agents are rational by studying in detail the equilibrium properties of a simple economy with quadratic preferences which captures, in turn, local preferences for conformity, habit persistence, and preferences for status or adherence to aggregate norms of behavior.     

Enterprise diversification in US dairy: impact of risk preferences on scale and scope economies

Enterprise diversification has recently become a prominent feature of US dairy farms. Scope economies and risk aversion are two forces that simultaneously determine diversification. We jointly estimate scope economies and determine risk preferences under price uncertainty. We reject risk neutrality in favour of Increasing Absolute Risk Aversion (IARA) and Increasing Relative Risk Aversion (IRRA). Scope economies are significant, but diminish with farm size. Increasing returns to scale exist in the production of multiple enterprises and diminish with size. Large farms operate under decreasing returns to scale. Ignoring risk preferences, a common practice in empirical work, results in an underestimate of the effect of scope economies for large farms.     

General equilibrium without utility functions: how far to go?

How far can we go in weakening the assumptions of the general equilibrium model? Existence of equilibrium, structural stability and finiteness of equilibria of regular economies, genericity of regular economies and an index formula for the equilibria of regular economies have been known not to require transitivity and completeness of consumers’ preferences. We show in this paper that if consumers’ non-ordered preferences satisfy a mild version of convexity already considered in the literature, then the following properties are also satisfied: (1) the smooth manifold structure and the diffeomorphism of the equilibrium manifold with a Euclidean space; (2) the diffeomorphism of the set of no-trade equilibria with a Euclidean space; (3) the openness and genericity of the set of regular equilibria as a subset of the equilibrium manifold; (4) for small trade vectors, the uniqueness, regularity and stability of equilibrium for two version of tatonnement; (5) the pathconnectedness of the sets of stable equilibria.     

Strategy-proofness versus efficiency for small domains of preferences over public goods

Summary. It has long been known that when agents have von Neumann-Morgenstern preferences over lotteries, there is an incompatibility between strategy-proofness and efficiency (Gibbard, [9]; Hylland, [12]) – a solution satisfying those properties must be dictatorial. We strengthen this result by showing that it follows from the same incompatibility on a series of much smaller domains of preferences. Specifically, we first show the incompatibility to hold on our smallest domain, in which two agents are restricted to have linear preferences over one private good and one public good produced from the private good (Kolm triangle economies). This result then implies the same incompatibility on increasingly larger domains of preferences, ending finally with the class of von Neumann-Morgenstern preferences over lotteries. Received: February 6, 1997; revised version: January 29, 1998     

Credit quantity and credit quality: Bank competition and capital accumulation

In this paper we show that bank competition has an intrinsically ambiguous impact on capital accumulation. We further show that it is also responsible for the emergence of development traps in economies that otherwise would be characterized by unique equilibria. These results explain the conflicting evidence emerging from the recent empirical studies of the effects of bank competition on economic growth. We obtain them developing a dynamic, general equilibrium model of capital accumulation where banks operate in a Cournot oligopoly. More banks lead to a higher quantity of credit available to entrepreneurs, but also to diminished incentives to offer relationship services that improve the likelihood of success of investment projects. We also show that conditioning on one key parameter resolves the theoretical ambiguity: in economies where intrinsic market uncertainty is high (low), less (more) competition leads to higher capital accumulation.     

Notes on economic equality

In this paper we propose a simple definition of economic equality and characterize non- paternalist egalitarian preferences. We compare our definition to the ideas of envy and fairness and extend these ideas to the case of extended benevolent preferences. In productive economies efficiency and equality may conflict, just as do efficiency and the absence of envy. We suggest a feasible compromise in this case.     

Are microfinance markets monopolistic?

Do microfinance institutions (MFIs) operate in a monopoly, monopolistic competition environment or are their revenues derived under perfect competition markets? We employ the Panzar–Rosse revenue test on a global panel data to assess the competitive environment in which MFIs of five selected countries operate: Ecuador, India, Indonesia, Peru and Philippines, over the period 2005–2009. We estimate the static and the dynamic revenue tests, with analyses of the interest rate and the return on assets. We control for microfinance-specific variables such as capital-assets-ratio, loans-assets and the size of the MFI. The analyses also account for the endogeneity problem by employing the fixed-effects two-stage least squares and the fixed-effects system generalized method of moments. Our results suggest that MFIs in Peru and India operate in a monopolistic environment. We also find weak evidence that the microfinance industry in Ecuador, Indonesia and Philippines may operate under perfect competition.     

Comparing Sunspot Equilibrium And Lottery Equilibrium Allocations: The Finite Case*

Sunspot equilibrium and lottery equilibrium are two stochastic solution concepts for nonstochastic economies. We compare these concepts in a class of completely finite, (possibly) nonconvex exchange economies with perfect markets, which requires extending the lottery model to the finite case. Every equilibrium allocation of our lottery model is also a sunspot equilibrium allocation. The converse is almost always true. There are exceptions, however: For some economies, there exist sunspot equilibrium allocations with no lottery equilibrium counterpart.     

Incentive Mechanism Design for Production Economies with Both Private and Public Ownerships

In this paper we deal with the problem of incentive mechanism design which yields efficient allocations for general mixed ownership economies when preferences, individual endowments, and coalition patterns among individuals are unknown to the planner. We do so by doubly implementing the proportional solution for economies with any number of private sector and public sector commodities and any number of individuals as well as the coexistence of privately and publicly owned firms with general convex production possibility sets. Furthermore, the mechanisms work not only for three or more agents, but also for two-agent economies. Journal of Economic Literature Classification Numbers: C72, D61, D71, D82.     

A testable model of consumption with externalities

This paper presents a nonparametric model of interdependent preferences, where an individual's consumption may act as an externality on the preferences of other consumers. We assume that individual price consumption data is observed for all consumers. It is known that the general consumption model with externalities imposes few restrictions on the observed data, where the consistency requirement is Nash rationalizability. We motivate potential games as an important sub class of games where the family of concave potential games is refutable and imposes stronger restrictions on observed data. We use this framework to extend the analysis of Brown and Matzkin [D. Brown, R. Matzkin, Testable restrictions on the equilibrium manifold, Econometrica 64 (1996) 1249-1262] on refutable pure exchange economies to pure exchange economies with externalities. Finally, we discuss an application of this model to inter-household consumption data.     

Measuring productivity in an imperfect world

Most measures of multifactor productivity (MFP) assume constant returns to scale and perfect competition. Using a general aggregate production function together with duality theory and allowing for the possibilities of disequilibrium, markups and economies of scale, the study derives a more generalized MFP measure. The model was used to assess the economic performance in US manufacturing for the 1949 to 1988 period. The results suggest that scale and markups have substantial power in explaining MFP growth for all periods and that half of the measured MFP growth (as measured within the conventional framework) comes from biases due to scale economies, market power, and interaction effects.     

Production equilibria in vector lattices

The general purpose of this paper is to prove quasiequilibrium existence theorems for production economies with general consumption sets in an infinite dimensional commodity space, without assuming any monotonicity of preferences or free-disposal in production. The commodity space is a vector lattice commodity space whose topological dual is a sublattice of its order dual. We formulate two kinds of properness concepts for agents' preferences and production sets, which reduce to more classical ones when the commodity space is locally convex and the consumption sets coincide with the positive cone. Assuming properness allows for extension theorems of quasiequilibrium prices obtained for the economy restricted to some order ideal of the commodity space. As an application, the existence of quasiequilibrium in the whole economy is proved without any assumption of monotonicity of preferences or free-disposal in production. Received: March 9, 1999; revised version: September 4, 2000     

转轨经济中自然垄断产业的竞争与所有制研究

竞争与所有制改革是目前自然垄断产业规制改革的主要趋势.但原有的理论和经验都是针对发达国家而言,对于转轨国家如何协调经济转轨与自然垄断产业改革却没有现成的理论与经验.因此,本文关注转轨国家自然垄断产业引入竞争可能性以及所有制改革模式的选择.研究发现:考虑管理成本,转轨国家自然垄断产业引入竞争是可能的;改革进程取决于转轨国家市场发育程度以及改革的初始条件;混合所有制的企业竞争模式更适合于转轨国家自然垄断产业的改革.