Absorbing sets in roommate problems

We analyze absorbing sets as a solution for roommate problems with strict preferences. This solution provides the set of stable matchings when it is non-empty and some matchings with interesting properties otherwise. In particular, all matchings in an absorbing set have the greatest number of agents with no incentive to change partners. These “satisfied” agents are paired in the same stable manner. In the case of multiple absorbing sets we find that any two such sets differ only in how satisfied agents are matched with each other.     

Notes on marriage markets with weak externalities

We consider marriage markets with externalities. We focus on weak externalities, that is, markets in which each agent is primarily concerned about her partner. We formalize and prove the claim that weak externalities are not so significant in the marriage market: in this case, the ω-core and the α-core coincide and are both nonempty. In addition, we show that, if we allow agents to block matchings without changing their mate, the results do not longer hold.     

企业核心竞争力和非核心竞争力竞争追随与均衡

企业核心和非核心竞争力追随会导致其竞争力升级和竞争力趋同。构建了企业核心和非核心竞争力竞争追随模型,讨论了在竞争追随条件下的核心和非核心竞争力的发展追随规律。     

Competition and monopoly of Chinese rural groundwater market：structure and determinants

China is facing severe problem of water scarcity.Agricultural sector,the main consumer of water resource,has remarkably changed its institutions on water resource deployment,due to heavy environmental pressure.As a new and spontaneous institution,groundwater market has developed rapidly in northern China,and has impacts on waterusing behaviors and benefits of farmers.Using household survey data from Hebei and Henan in 2007,this paper attempts to pin down the development and operating of groundwater market in rural China.We focus on the monopoly and competition in the market.Empirical analysis reveals that Chinese farmers are trying to make rational decision when they compete with others in groundwater market.In general,monopoly is not fierce in Chinese rural groundwater market,with great variations among different villages and even different tubewells within one village.Tubewell costs,regulation and the density of tubewells are the main determinants that affect monopoly level of groundwater market.To make water market benefit more and more farmers of low income,corresponding policies are needed to modify its development in the future.     

Harmful signaling in matching markets

Several labor markets, including the job market for new Ph.D. economists, have recently developed formal signaling mechanisms. We show that such mechanisms are harmful for some environments. While signals transmit previously unavailable information, they also facilitate information asymmetry that leads to coordination failures. In particular, we consider a two-sided matching game of incomplete information between firms and workers. Each worker has either the same “typical” known preferences with probability close to one or “atypical” idiosyncratic preferences with the complementary probability close to zero. Firms have known preferences over workers. We show that under some technical condition if at least three firms are responsive to some workerʼs signal, the introduction of signaling strictly decreases the expected number of matches.     

Imperfect competition in two-sided matching markets

This paper considers a simple equilibrium model of an imperfectly competitive two-sided matching market. Firms and workers may have heterogeneous preferences over matches on the other side, and the model allows for both uniform and personalized wages or contracts. To make the model tractable, I use the Azevedo and Leshno (2013) framework, in which a finite number of firms is matched to a continuum of workers.In equilibrium, even if wages are exogenous and fixed, firms have incentives to strategically reduce their capacity, to increase the quality of their worker pool. The intensity of incentives to reduce capacity is given by a simple formula, analogous to the classic Cournot model, but depends on different moments of the distribution of preferences. I compare markets with uniform and personalized wages. For fixed quantities, markets with personalized wages always yield higher efficiency than markets with uniform wages, but may be less efficient if firms reduce capacity to avoid bidding too much for star workers.     

Competition policy in open economies

Abstract

This paper examines aspects of R&;D spillovers across countries, in particular, the role of international trade and human capital as the catalysts for international diffusion of technology. We present a new way of measuring foreign R&;D stocks embodied in foreign intermediate goods and capital equipment, which we argue is free from the criticism of previous measures. With the pooled panel data spanning 1970 through 1995 for 103 countries, we find that the effects of foreign R&;D on total factor productivity growth of both industrial countries and developing countries are substantial and that human capital is the most influential channel for absorbing foreign R&;D spillovers.     

Incentives in decentralized random matching markets

Decentralized markets are modeled by means of a sequential game where, starting from any matching situation, firms are randomly given the opportunity to make job offers. In this random context, we prove the existence of ordinal subgame perfect equilibria where firms act according to a list of preferences. Moreover, every such equilibrium preserves stability for a particular profile of preferences. In particular, when firms best reply by acting truthfully, every equilibrium outcome is stable for the true preferences. Conversely, when the initial matching is the empty matching, every stable matching can be reached as the outcome of an ordinal equilibrium play of the game.     

Competition and collusion in bilateral markets

In this paper, the core of a market game which constitutes the set of equilibria in the process of competitive contracting and recontracting is criticized as a solution concept for not being immune against theory absorption in the sense that knowledge of the core on part of the traders may result in a collusive stabilization of some dominated imputation. It is pointed out that a stable set (or, von Neumann-Morgenstern) solution does not suffer from this deficiency. Moreover, it is argued that stable set solutions provide an adequate analytical framework for the study of collusion, and are in this respect superior to the approach (relying on the core concept) chosen by Aumann in his work on disadvantageous monopolies. For symmetric bilateral market games — generated by markets involving the exchange of only two commodities, one of which also serves as a means of side payment and utility transfer, among two types of traders — with one seller and one up to three buyers all symmetric solutions are determined. Furthermore, a symmetric solution for markets with equal, but otherwise arbitrary, numbers of sellers and buyers is given. The symmetric stable sets of imputations are interpreted as rational standards of behavior providing the consistent and defensible rules of division necessary to make a cartel agreement viable.This research was partially supported by a grant given to New York University, Department of Economics, by the Office of Naval Research. (# N00014-76-C-0033). A first version of the paper was presented at the Third World Congress of the Eeconomtric Society, Toronto, Aug. 20–26, 1975, under the title Symmetric Solutions of Bilateral Market Games.     

Optimal truncation in matching markets

Although no stable matching mechanism can induce truth-telling as a dominant strategy for all participants (Roth, 1982), recent studies have presented conditions under which truthful reporting by all agents is close to optimal (Immorlica and Mahdian, 2005, Kojima and Pathak, 2009, Lee, 2011). Our results demonstrate that in large, uniform markets using the Men-Proposing Deferred Acceptance Algorithm, each woman's best response to truthful behavior by all other agents is to truncate her list substantially. In fact, the optimal degree of truncation for such a woman goes to 100% of her list as the market size grows large. In general one-to-one markets we provide comparative statics for optimal truncation strategies: reduction in risk aversion and reduced correlation across preferences each lead agents to truncate more. So while several recent papers focused on the limits of strategic manipulation, our results serve as a reminder that without pre-conditions ensuring truthful reporting, there exists a potential for significant manipulation even in settings where agents have little information.     

Competition and production prices

My theorem, the so-called Okishio theorem, is a comparativestatics result. Therefore, it has no realistic meaning if capitalists'competition does not establish a new equilibrium following theintroduction of a new production method. Marx firmly believedthat a new equilibrium was established. In this paper, we investigatethe capitalist process without technical change. If we choosethe proper parameters and initial conditions, all profit ratesconverge to zero, Schumpeter's result.     

Competition and corruption in an agency relationship

The paper reconsiders the relationship between competition and corruption in a model, where corruption has solid informational foundations and where the regulatory response to the possibility of corruption is taken into account. It is shown that the effect of greater competition on corruption depends on the complementarity or substitutability of the two instruments available to decrease information rents, namely low powered incentives and greater competition. The paper concludes with a brief empirical exploration of the relationship between competitiveness and corruption on African data.     

Competition and Price Dispersion in International Long-distance Calling

This paper examines the relationship between changes in telecommunications provider competition on international long-distance routes and changes in prices. Overall, increased competition is associated with significantly lower prices to consumers of long-distance services. However, the relationship between competition and price varies according to the type of long-distance plan considered. For the plans frequently selected by price-conscious consumers, increased competition on a route is associated with lower prices. In contrast, for the basic international plans that are the default selection for consumers, increased competition on a route is actually associated with higher prices. Thus price dispersion appears to increase as competition increases. The views expressed in this paper are those of the author and not necessarily those of the OECD. I thank two anonymous referees, Joe Farrell, John Harkrider, Jim Lande, Bob Majure, Carl Willner and seminar participants at the FCC for their helpful comments. Special thanks for aid with data to Linda Blake, Mark Uretsky, Jim Lande, R.L. Smith and Carl Willner.     

Competition and waiting times in hospital markets

This paper studies the impact of hospital competition on waiting times. We use a Salop-type model, with hospitals that differ in (geographical) location and, potentially, waiting time, and two types of patients: high-benefit patients who choose between neighbouring hospitals (competitive segment), and low-benefit patients who decide whether or not to demand treatment from the closest hospital (monopoly segment). Compared with a benchmark case of monopoly, we find that hospital competition leads to longer waiting times in equilibrium if the competitive segment is sufficiently large. Given a policy regime of hospital competition, the effect of increased competition depends on the parameter of measurement: Lower travelling costs increase waiting times, higher hospital density reduces waiting times, while the effect of a larger competitive segment is ambiguous. We also show that, if the competitive segment is large, hospital competition is socially preferable to monopoly only if the (regulated) treatment price is sufficiently high.     

Asymmetric correlations in gold and other financial markets

In this article, we implement a recently developed statistical method to test asymmetries in cross-asset correlations, focusing in particular on the gold market. Our empirical results provide evidence that gold exhibits asymmetric correlations with stocks and the U.S. dollar, but not with bonds. Furthermore, splitting the sample into three characteristic periods, we find that exceedance correlations exhibit substantial time variation even in similar market tensions for same pairs of assets. Our findings imply that investors and fund managers should take into account the asymmetric dependence structure, which depends on the upside or downside of the market.     

银行业的集中、竞争与绩效

各国金融资产配置方式不同 ,银行业的产业组织结构也存在鲜明的差异。与传统的产业组织理论的逻辑推论及其倡导的理想境界可能完全相反 ,由大规模银行组成的相对集中的产业组织结构并不一定导致竞争程度的下降。中国银行业偏高的集中率并不是影响行业竞争程度的原因 ,事实表明 ,中国各银行之间在存贷业务及其他业务上并不缺乏竞争。主要问题在于现有的国有银行经营机制不灵活、效率过低。即使中国银行业大幅度提高了商业化程度 ,银行业的产业组织结构也不宜于过度分散 ,保持相对集中的行业结构 ,可能更有利于提高金融资产的配置效率。     

Competition among auctioneers in large markets

We analyse a multistage game of competition among auctioneers. First, the auctioneers commit to some reserve prices; second, the bidders enter one auction, if any; and finally, the auctions take place. We show that for any finite set of feasible reserve prices, each auctioneer announces a reserve price equal to his production cost if the numbers of auctioneers and bidders are sufficiently large, though finite. Our result supports the idea that optimal auctions may be quite simple. Our model also confirms previous results for some “limit” versions of the model by McAfee (Econometrica 61 (1993) 1281-1312), Peters (Rev. Econ. Stud. 64 (1997) 97-123), and Peters and Severinov (J. Econ. Theory 75 (1997) 141-179).     

Oligopoly equilibria in electricity contract markets

This paper examines the implications of forward contracting on oligopoly environments by extending the model of Allaz and Vila to an environment with multiple firms and increasing marginal cost. Estimates of key parameters of this model are taken from existing electricity markets to predict the market impact of one round of public contracting, such as those seen in auctions for retail provision and resource procurement. The results imply that, when forward contracts are present, the importance of supplier concentration is greatly magnified relative to other determinants unilateral market power such as demand elasticity.      

开发区核心竞争力的概念及分析框架

回顾了开发区核心竞争力的研究状况,总结了目前学术界关于开发区核心竞争力的主要观点与论述。根据核心竞争力的本质,讨论了开发区核心竞争力的概念、内涵、特征以及构成。最后给出了开发区核心竞争力的分析框架,以便为开发区核心竞争力的研究提供一个规范的思路。     

Competition and price dispersion in the airline markets

We use two ticket-level data sets on one-way domestic flights for the US airlines to examine the potentially nonlinear relationship between price dispersion and three forms of competition: inter-firm, inter-flight and frequency competitions. The linear relationship is rejected at any conventional significance levels. In particular, there is an S-shaped relationship between market concentration and price dispersion. This can be a reason for the mixed results in the literature. Roughly speaking, the inter-flight and frequency competitions have opposite effects on price dispersion. Finally, in general, the size of aircraft has a positive effect on price. However, for very large aircraft, the relationship becomes negative.