Gains and losses at core allocations

The search for a coalition which can possibly improve upon a given allocation and the redistribution of endowments within such a coalition are conducted through the use of prices. Prices permit the expression of how much every agent gains or loses in the allocation. With any feasible allocation one can associate a price system such that either the total loss of all losers does not exceed a certain bound independent of the number of agents or the losers can improve. The definition of gains and losses that we use implies that the total gain is also bounded in core allocations. Our theorem is closely related to that of Vind (1965).     

On characterizing the probability of survival in a large competitive economy

We consider a Walrasian exchange economy in which an agent is characterized by a utility function, a random endowment vector, and a function that specifies the minimum expenditure necessary for survival at a given price system. If at any equilibrium price system, the income of the agent is no more than the minimum expenditure for survival, it is ruined. The main results characterize the probability of ruin when the number of agents is large. The implications of stochastic dependence among agents are explored.     

Equitable nature of core allocations in atomless economies

The purpose of this paper is to prove the equal treatment property for the -core allocations of an atomless economy without any condition on the data of economy. This result prompts the same property for the core allocations. Received: 7 March 1995 / Accepted: 3 March 1997     

On optimal allocations for estimating the surface of a random field

In general, the construction of optimal designs is apparently a difficult task for the approximation of a random field indexed by more than one dimension. Besides the rate of convergence of the minimum achievable error hardly anything is known until now. However, if there is an immanent structure present in the random field, then, taking this structure into account, improved estimates can be obtained. For this situation we present adequate designs which show, at least, a nearly optimal performance. work supported by 313/ARC/VII/93/151 of the DAAD work supported by Ku719/2-1 of the DFG     

城市经济发展中特色经济与集群经济的关系--兼论城市园区经济建设

特色经济与集群经济现在是城市经济发展过程中两个彰显的概念,二者从不同角度阐释了城市经济发展的基本要求.特色经济反映的是城市经济的质,而集群经济反映的是城市经济的量.没有特色的城市经济缺乏活力和竞争力,没有集群的特色经济则对城市经济的带动作用就微乎其微.二者的有机统一才是最具活力和竞争力的城市经济单元.     

The epsilon core of a large replica game

Sufficient conditions are given for large replica games without side payments to have non-empty approximate cores for all sufficiently large replications. No ‘balancedness’ assumptions are required. The conditions are superadditivity, a boundedness condition, and convexity of the payoff sets.     

Equilibria and core of large economies

In this paper we apply results on regular economies to study equilibria and core in a non-differentiable framework. We show that the distributions of agents' characteristics of regular economies form a dense subset of all distributions of agents' characteristics. Therefore ‘most’ economies have equilibria which are contained in finitely many ?-balls. And the core of ‘most’ sufficiently large economies is contained in finitely many ?-balls centered at equilibrium allocations of these economies.     

On the relative precision of several allocations in stratified sampling

MOORS (1973) gave lower bounds for the relative precision of different allocations compared to Neyman allocation in stratified sampling. These results are extended here to the relative precision with respect to optimal allocation. A result of COCHRAN (1977) is generalized.     

An elementary core equivalence theorem¶in a countable economy

We consider an infinite exchange economy with countably many traders, which can be regarded as a natural extension of finite exchange economies to an infinite one. In our countable economy the core defined in the traditional manner would be empty. To avoid this unwanted situation we have to strengthen the notion of “improves upon”. We will achieve this based on the idea that forming coalitions involve costs. Received: 23 August 2000 / Accepted: 12 April 2002 I am very grateful to István Dancs, Péter Medvegyev, Miklós Pintér, Csaba Sándor, András Simonovits, László Szili, Péter Tallos and the anonymous referees for comments and suggestions. Parts of this research were done during the author's Bolyai János Research Fellowship provided by the Hungarian Academy of Sciences (MTA). Of course, all errors remain the author's responsibility.     

The Walras core of an economy and its limit theorem

The Walras core of an economy is the set of allocations that are attainable for the consumers when their trades are constrained to be based on some agreed price system, such that no alternative price system exists for any sub-coalition that allows all members to trade to something better. As compared with the Edgeworth core, both coalitional improvements and being a candidate allocation for the Walras core become harder. The Walras core may even contain allocations that violate the usual Pareto efficiency. Nevertheless, the competitive allocations are the same under the two theories, and the equal-treatment Walras core allocations converge under general conditions to the competitive allocations in the process of replication.     

谈市场经济条件下的企业理财观念

观念的转变具有时间的滞后性 ,因此需要就企业界尚存的传统理财观念进行反思与剖析 ,并按照市场经济规律的内在要求 ,提出与国际惯例接轨的全新理财观念     

Theorems on the core of an economy with infinitely many commodities and consumers

It is known that the classical theorems of Grodal [Grodal, B., 1972. A second remark on the core of an atomless economy. Econometrica 40, 581–583] and Schmeidler [Schmeidler, D., 1972. A remark on the core of an atomless economy. Econometrica 40, 579–580] on the veto power of small coalitions in finite dimensional, atomless economies can be extended (with some minor modifications) to include the case of countably many commodities. This paper presents a further extension of these results to include the case of uncountably many commodities. We also extend Vind’s [Vind, K., 1972. A third remark on the core of an atomless economy. Econometrica 40, 585–586] classical theorem on the veto power of big coalitions in finite dimensional, atomless economies to include the case of an arbitrary number of commodities. In another result, we show that in the coalitional economy defined by an atomless individualistic model, core–Walras equivalence holds even if the commodity space is non-separable. The above-mentioned results are also valid for a differential information economy with a finite state space. We also extend Kannai’s [Kannai, Y., 1970. Continuity properties of the core of a market. Econometrica 38, 791–815] theorem on the continuity of the core of a finite dimensional, large economy to include the case of an arbitrary number of commodities. All of our results are applications of a lemma, that we prove here, about the set of aggregate alternatives available to a coalition. Throughout the paper, the commodity space is assumed to be an ordered Banach space which has an interior point in its positive cone.     

Rational expectations equilibria and the ex-post core of an economy with asymmetric information

We study the relationship between the set of rational expectations equilibrium allocations and the ex-post core of exchange economies with asymmetric information.     

Risky allocations from a risk-neutral informed principal

We study a model of informed principal with private values where the principal is risk neutral and the agent is risk averse. We show that the principal, regardless of her type, gains by not revealing her type to the agent through the contract offer. The equilibrium allocation transfers some ex-ante risk from one type of agent to the other. Despite the increase in the principal's surplus, allocative efficiency does not necessarily improve. Received: 26 January 2004, Accepted: 5 May 2005 JEL Classification: C72, D23, D82 I would like to thank my supervisor Leonardo Felli for suggestions and Leo Ferraris for helpful discussions. All remainig errors are my own.     

Homeownership and mixed-asset portfolio allocations

Homeownership represents both a consumption and an investment decision for individuals. Considering the investment benefits of the home, we estimate the total returns and risk associated with the investment in single-family homes. Then, using a mean–variance utility function, we consider the impact of homeownership and mortgage loan financing on the optimal asset allocation decisions of individuals and contrast this with advice that does not include the home as part of the portfolio. While optimal portfolio weights are dependant upon both the degree of risk aversion of the individual investor and the relative importance of the home in the overall net worth picture, we show that, in general, the higher the home-to-net worth ratio, the higher the optimal portfolio allocation to stock. For most investors, including the home in the optimization decision leads to higher allocations to risky stock than suggested by traditional advice that ignores the home.     

How large is Vietnam's informal economy?

The purpose of this article is to estimate the size of the informal economy in Vietnam, describe its development from 1995 to 2015, and assess the country's potential tax loss from this activity. The MIMIC model indicates that the informal economy accounts for between 15 per cent and 27 per cent of GDP. The informal economy has grown sharply in Vietnam since 2007, while its size has decreased in other comparable nations. Potential tax revenue lost annually amounts to between 3.3 per cent and 5 per cent of gross domestic product.