Existence of expectation equilibrium of real asset economies with transaction costs

Abstract. To some two period economies with countable infinite state spaces, the existence of expectation equilibrium of real asset economies with transaction costs is given. This work extends the researches of Zame in 1993.     

Existence of equilibrium for economies with infinitely many commodities and infinitely countable consumers

This paper examines the existence of equilibria for double infinite eonomies. S.F. Richard and S. Srivastava have established the existence of equilibria for economies with infinitely countable consumers when commodity space isL ^∞ (M, M, μ). However, most Banach Lattices as commodity spaces haven’t interior points in their positive cones, so their result can’t be applied to many cases. We here consider a general Banach Lattice as commodity space and introduce a concept of equiproperness on preferences. Under the assumption the existence of equilibrium for economy is established. Finally, we examine the existence of equilibria for production economies.     

Approximate cores of replica games and economies: Part II: Set-up costs and firm formation in coalition production economies

A model of a coalition production economy allowing set-up costs, indivisibilities,and nonconvexities is developed. It is shown that for all sufficiently large replications, approximate cores of the economy are nonempty.     

Existence of a pareto equilibrium

In this paper, we investigate the existence of Pareto equilibria in multicriteria games. The investigation is carried out in two ways: one follows the fixed-point technique, and the other utilizes other tools. Several sufficient conditions are presented to guarantee the existence of a Pareto equilibrium.This research was supported by NSFC under Grant No. G-78-900011 and by BMADIS. The author is grateful to the referees for supplying several valuable comments and suggestions.     

On variational stability in competitive economies

We explore the variational stability of supply, demand and equilibria in perfectly competitive economies. The appropriate and, in fact, minimal limit notion is furnished by the Kuratowski-Painlevé concept of set convergence together with its functional analogues epi and hypo convergence. When technologies and preferences converge is such manners we show, subject to compactness assumptions, that observable features of approximate economies cluster to those of the limiting economy. Such findings are important in applied economic analysis.Research partially supported by Université de Perpignan. Thanks are due R. Lucchetti and two referees.     

Existence of a Radner equilibrium in a model with transaction costs

We prove the existence of a Radner equilibrium in a model with proportional transaction costs on an infinite time horizon and analyze the effect of transaction costs on the endogenously determined interest rate. Two agents receive exogenous, unspanned income and choose between consumption and investing into an annuity. After establishing the existence of a discrete-time equilibrium, we show that the discrete-time equilibrium converges to a continuous-time equilibrium model. The continuous-time equilibrium provides an explicit formula for the equilibrium interest rate in terms of the transaction cost parameter. We analyze the impact of transaction costs on the equilibrium interest rate and welfare levels.     

Existence of intransitive equilibria in nonconvex economies

We consider a general equilibrium model of an economy with increasing returns to scale or more general types of nonconvexity and without ordered preferences. Firms are instructed to set their prices according to general pricing rules which may depend on the production plans of other firms. We suppose, moreover, that the pricing rule of the firms verifies a condition of weak bounded losses. This includes the case of profit maximizing, average cost pricing and marginal (cost) pricing, thanks to a transformation used by Bonnisseau. The tastes of the consumers may depend both on other consumptions and on the prices This paper reports a general existence result in this model which extends the results of Bonnisseau and Cornet.     

General equilibrium and social choice in economies with increasing returns

For any intransitive community preference, we construct a non-convex economy where all the marginal cost pricing general equilibria are Pareto inefficient (theorem 3.2). The result is valid without requiring a fixed income distribution rule (corollary 3.3). Intransitive community preferences are a frequent occurrence (theorem 3.1): necessary and sufficient conditions for transitivity of the community preference fail in a set which is open and dense in the space of individual preferences with a standard topology.     

Natural implementation with semi-responsible agents in pure exchange economies

We study Nash implementation by natural price–quantity mechanisms in pure exchange economies when agents have intrinsic preferences for responsibility. An agent has an intrinsic preference for responsibility if she cares about truth-telling that is in line with the goal of the mechanism designer besides her material well-being. A semi-responsible agent is an agent who, given what her opponents do, acts in an irresponsible manner when a responsible behavior poses obstacles to her material well-being. The class of efficient allocation rules that are Nash implementable is identified provided that there is at least one agent who is semi-responsible. The Walrasian rule is shown to belong to that class.     

EXISTENCE OF STOCHASTIC EQUILIBRIUM WITH INCOMPLETE FINANCIAL MARKETS

This paper analyzes the aritrage-tree security markets and the general equilibrium ex-istence problem for a stochastic economy with incomplete financial markets. Information structure is given by an event tree. This paper restricts attention to puraly financial securities. It isassume that trading takes place in the sequence of spot markets and futures markets for securi-ties payable in units of account. Unlimited short-selling in securities is allowed. Financial markets may be incomplete, some consumption streams may be impossible to obtain by any tradingstrategy. Securities may be individually precluded from trade at arbitrary states and dates. Thesecurity price process is arbitrage-free the dividend process if and only if there exists a stochaticstate price (present value) process : the present value of the security prices at every vertex isthe present value of their dividend and capital values over the set of immediate successors ; thecurrent value of each security at every vertex is the present value of its future dividend streamover all succeeding vertices. The existence of such an equilibrium is proved under the followingcondition: continuous, weakly convex, strictly monotone and complete preferences, strictlypositive endowmenta and dividends processes.     

Secure implementation in production economies

This paper shows that, in production economies, the generalized serial social choice functions defined by Shenker (1992) are securely implementable (in the sense of  Saijo et al., 2007) and that they include the well-known fixed path social choice functions.     

A new contribution to a dynamic competitive equilibrium problem

The aim of this paper is to study the Walrasian equilibrium problem when the data are time dependent. For this model an existence result is provided using the variational inequality theory in infinite dimensional spaces. Our results are the generalization of some of the results obtained by several authors in the static case (see e.g. Donato et al. (2008) [5], Donato et al. (2008) [4] and Mordukhovich (2006) [11], Nagurney (1993) [2] and the references therein).     

Existence of equilibrium pairs in continuous games

It is shown that all continuous two-person general-sum games over the square have equilibrium pairs of mixed strategy. A slight extension of Helly's Second Theorem, which may be of some slight interest in its own right, is used. The result is then generalized to all continuousn-person games on the cube.     

Existence theorems of equilibrium points in stackelberg

A two players static. Stackelberg game is considered with constraints on the decision variables. Existence theorems of equilibrium points are given when the reaction set of the follower to the strategy of the leader, is a singleton. Some definition are presented and discussed and a simple existence theorem is given also in the case when the follower has more than one element in his reaction set. Finally an example of dynamic Stackelbebg game- is analized to emphasize some features arising when constraints are present on control variables.     

Equilibria in abstract economies with a measure space of agents and with an infinite dimensional strategy space

Khan's result [7, 8] on equilibrium points of non-atomic games is generalized to a setting where agents' preferences need not be ordered.     

Existence theorems via duality for equilibrium problems with trifunctions

We present an existence result for an equilibrium problem formulated with trifunctions, which is motivated by variational inequalities governed by quasimonotone operators. To prove the existence result, we define the dual problem, and some monotonicity notions for trifunctions. From the main result follow, among others, the Browder–Minty theorem for variational inequalities and Ky Fan’s Minimax theorem. Some applications for mixed equilibrium problems and variational inequalities are given.     

A FPTAS for computing a symmetric Leontief competitive economy equilibrium

In this paper, we consider a linear complementarity problem (LCP) arisen from the Nash and Arrow–Debreu competitive economy equilibria where the LCP coefficient matrix is symmetric. We prove that the decision problem, to decide whether or not there exists a complementary solution, is NP-complete. Under certain conditions, an LCP solution is guaranteed to exist and we present a fully polynomial-time approximation scheme (FPTAS) for approximating a complementary solution, although the LCP solution set can be non-convex or non-connected. Our method is based on approximating a quadratic social utility optimization problem (QP) and showing that a certain KKT point of the QP problem is an LCP solution. Then, we further show that such a KKT point can be approximated with a new improved running time complexity ${{O}((\frac{n^4}{\epsilon})\log\log(\frac{1}{\epsilon}))}$ arithmetic operation in accuracy ${\epsilon \in (0,1)}$ . We also report preliminary computational results which show that the method is highly effective. Applications in competitive market model problems with other utility functions are also presented, including global trading and dynamic spectrum management problems.