Equilibrium in incomplete markets: II : Generic existence in stochastic economies

We model multiperiod securities markets with differential information. A price system that admits no free lunches is related to martingales when agents have rational expectations. We introduce the concept of resolution time, and show that a better informed agent and a less informed agent must agree on the resolution times of commonly marketed events if they have rational expectations and if there are no free lunches. It then follows that if all elementary events are marketed for a less informed agent then any price system that admits no free lunches to a better informed agent must eliminate any private information asymmetry between the two. We provide an example of a dynamically fully revealing price system that is arbitrage free and yields elementarily complete markets.     

On the existence,uniqueness and stability of spatial equilibrium in an open city with externalities

This paper deals with the existence, uniqueness and stability of a spatial equilibrium in an open city with external diseconomies like air pollution generated by manufacturing activities. First, assuming that both production functions and utility functions are Cobb-Douglas, we prove the existence of a spatial equilibrium under some reasonable assumptions. It is shown, however, that the uniqueness and stability of the equilibrium may not be obtained, unless the degree of externality is sufficiently small. In fact, none of the equilibria will be stable for a certain set of speeds of adjustment in the labor market and the land market, if the degree of externality is relatively large. Finally, some implications of our results are derived in regard to the application of the hedonic price concept within the context of a spatial equilibrium model.     

Equilibrium in abstract economies without ordered preferences

We extend a theorem of G. Debreu on the existence of equilibrium in a generalized N-person game (‘A Social Equilibrium Existence Theorem’). Applying standard techniques the result can be used to prove the existence of equilibrium in economies with interdependent preferences, price-dependent preferences and preferences which may be both non-transitive and non-complete. This generalizes a recent theorem of A. Mas-Colell.     

On the existence of walrasian equilibrium in large-square economies

An existence theorem for Walrasian equilibrium is demonstrated for an economy with a continuum of consumers and an infinite-dimensional commodity space, such as l₁ or c₀, having an ‘order-compatible’ basis.     

Equilibrium in economies without ordered preferences or free disposal

Recent work in competitive equilibrium analysis, pioneered by Mas-Colell (1974), ‘An equil- brium existence theorem without complete or transitive preferences’, has established existence of equilibrium in an economy in which preferences are not orderings. The purpose of this note is to show that the assumption of free disposal is not necessary for existence.     

Equilibrium allocations of endowment-pretension games in public good economies

In a public good economy where agents' preferences are known but endowments are private information, instituting an allocation rule and asking the agents their initial endowments induces an endowment-pretension game. We analyse the Nash equilibrium allocations of this game and discuss its welfare properties with reference to voluntary contributions allocations. Received: 30 May 2001, Accepted: 23 September 2005 JEL Classification: H41 I am grateful to Murat Sertel for his continuous support and encouragement; to G?ksel Asan and Arunava Sen for their invaluable help. I would also like to thank Fikret Adaman, Ahmet Alkan, Salvador Barberá, Semih Koray, Andrei Ratiu, Muhamet Yíldíz, ünal Zenginobuz, an Associate Editor and two referees of the Review of Economic Design for their enlightening comments on previous drafts. Earlier versions of this paper were written during my stay at Universitat Autónoma de Barcelona and at the Indian Statistical Institute. Both visits have been possible by the kindness of the host institutions and the financial support of the Turkish Academy of Sciences and Serem Ltd. It is a pleasure for me to express my gratitude to all these institutions. Of course, all possible errors are mine.     

Equilibrium existence in Tullock contests with incomplete information

We prove an existence theorem for pure strategy Bayesian Nash equilibrium in Tullock contests where the information endowment of each contender is described by a countable partition.     

Bank competition,financial development and macroeconomic stability: Empirical evidence from emerging economies

In this study, we investigate the potential contribution of bank competition to macroeconomic stability, and the interactive role of financial development. We classify macroeconomic stability into economic and financial stability. Economic stability is represented by the volatility of actual and unexpected output growth, whereas financial stability is assessed by the aggregate Z-score and volatility of the private credit-to-gross domestic product ratio. We employ two structural and two non-structural measures of bank competition in our analysis. Applying a two-step dynamic panel system (GMM) to macroeconomic data from 48 developing nations from 1999 to 2018, we find a bell-shaped relationship between bank competition and macroeconomic stability. The findings imply that a higher level of bank competition promotes macroeconomic stability by reducing output growth volatility, fluctuations in private credit, and the probability of bank default. There is an optimal level of bank competition beyond which it may foster economic and financial instability. Moreover, financial development enhances bank competition’s positive impact on macroeconomic stability.     

The core-periphery model: A note on the existence and uniqueness of short-run equilibrium

We consider the core-periphery model [P. Krugman, Increasing returns and economic geography, Journal of Political Economy 199 (1) (1991) 483–499]. The nature and stability of the possible steady states of the model have been made progressively precise; [M. Fujita, P. Krugman, A. Venables, The Spatial Economy. Cities, Regions and International Trade, MIT Press, Cambridge, 1999; R. Baldwin, R. Forslid, Ph. Martin, G. Ottaviano, F. Robert-Nicoud, Economic Geography and Public Policy, Princeton Univ. Press, 2003]. In that model as well as in all the new economic geography models that have been derived from it, the short-run (instantaneous) equilibrium is implicitly determined by the current labor distribution across regions. The numerical computations used so far to determine the short-run equilibrium, tend to suggest its existence. In this paper, an existence and uniqueness proof of short-run equilibrium is provided.     

Equilibrium in incomplete markets: I : A basic model of generic existence

This paper demonstrates the generic existence of general equilibria in incomplete markets. Our economy is a model of two periods, with uncertainty over the state of nature to be revealed in the second period. Securities are claims to commodity bundles in the second period that are contingent on the state of nature, and are insufficient in number to span all state contingent claims to value, regardless of the announced spot commodity prices. Under smooth preference assumptions, equilibria exist except for an exceptional set of endowments and securities, a closed set of measure zero. The paper includes partial results for fixed securities, showing the existence of equilibria except for an exceptional set of endowments.     

Equilibrium analysis and envelope theory

Qualitative comparative statics amounts to a study of the qualitative properties of the Debreu mapping, i.e., the restriction of the projection (p,ω)?ω to the equilibrium manifold. We show that a natural framework for such a study is Thom's envelope theory which generalizes the theory of planar curve envelopes.     

Communication complexity and stability of equilibria in economies and games

The theory of decentralized allocation mechanisms introduced by Leonid Hurwicz enabled economists to analyze the implications of requiring an allocation mechanism to perform well over a range of possible economic environments. One of the earliest major results in this theory was the formalization and proof of Hayek’s famous assertion that the competitive market mechanism minimizes the communication needed to achieve Pareto efficient allocations. The informational efficiency theorem spawned a large literature on communication complexity in allocation mechanisms. This paper provides an exposition of some results on the communication required to make equilibria locally stable, and the possibility of eliciting the required communication in allocation mechanisms and games.     

On existence and uniqueness of maximum likelihood estimates in quantal and ordinal response models

Summary For quantal and ordinal response models, conditions on existence and uniqueness of maximum likelhood estimates are presented. Results are derived from general results on direction sets and spaces associated with a proper concave function. If each summand of the log likelihood is in any direction either strictly concave or affine, necessary and sufficient conditions are obtained. If all cell counts are strictly positive, then it is shown that estimates always exist, and that they are unique if all parameters are identifiable. If estimates exist without being unique, results on uniquely estimable linear functions are given, paralleling corresponding results in linear regression. An extension of the maximum likelihood principle is outlined yielding similar results even if the likelihood does not attain its supremum. The logit model, the linear probability model, cumulative and sequential models and binomial response models are considered in detail.     

Equilibrium in abstract economies without ordered preferences and with a measure space of agents

We report a generalization of Aumann's (1966) existence theorem to economies without ordered preferences and with externalities in consumption. Our work can alternatively be viewed as a generalization of the Shafer–Sonnenschein (1975) theorem to economies with a continuum of agents.     

On the existence of equilibria in economies with an infinite dimensional commodity space

We prove an infinite dimensional extension of the Gale–Nikaido–Debreu lemma which includes all necessary limiting processes and allows a proof of the existence of equilibria under standard assumptions in an economy with infinitely many commodities which exactly parallels the proof of Debreu (1959) for the finite dimensional case.     

Local industrial structure,agglomeration economies and the creation of innovative start-ups: evidence from the Italian case

We explore the local factors associated with the emergence of innovative start-ups fostered by a targeted industrial policy intervention in Italy. We focus on the local industrial fabric and the agglomeration mechanisms, namely localization (specialization) economies, diversification economies and the proximity to large firms. Results show that both localization economies and diversification economies are at play. Notably, a greater presence of large firms at local level seems to support the creation of innovative start-ups. Other factors, such us the presence of technical and scientific universities and the urbanization, are found to encourage their formation. The contribution of local factors to the innovative start-up creation is found to be different depending on the regional development conditions. Our analysis outlines the features of a local ecosystem favourable to the emergence of these firms, providing policy makers with suggestions for moulding industrial policies to regional specific needs and to better exploit the local opportunities.     

On existence and stability of spatial equilibria and steady-states

This note discusses the existence and stability of two equilibrium concepts for a spatial economy in which the utility of an agent depends on the overall distribution of agents over space.     

Efficiency in Third Sector Partnerships for Delivering Local Government Services: The role of economies of scale,scope and learning

Abstract

Third sector partnerships are under pressure to change in the light of the increasing cost pressures on local public services. The literature throws doubt on the level of economies of scale and suggests that more attention should be given to economies of scope and learning. The common conflation of economies of size with economies of scale has led policymakers to overemphasize larger scale providers and has distorted the strategies which third sector organizations have adopted, pushing them towards mergers and consortia based on scale.