Farsighted strategies in the formation of a communication network

I examine the formation of a specific communication network, a variant of the two-way flow model, in which agents have farsighted strategies. I show that the likelihood to form efficient networks tends to zero for sufficiently large network sizes.     

On the formation of interaction networks in social coordination games

There are many situations where two interacting individuals can benefit from coordinating their actions. We examine the endogenous choice of partners in such social coordination games and the implications for resulting play. We model the interaction pattern as a network where individuals periodically have the discretion to add or sever links to other players. With such endogenous interaction patterns we see multiple stochastically stable states of play, including some that involve play of equilibria in the coordination game that are neither efficient nor risk-dominant. Thus the endogenous network structure not only has implications for the interaction pattern that emerges, but it also has a significant impact on the play in the coordination game relative to what would arise if the same interaction network were exogenous.     

Strongly stable networks

We analyze the formation of networks among individuals. In particular, we examine the existence of networks that are stable against changes in links by any coalition of individuals. We show that to investigate the existence of such strongly stable networks one can restrict focus on a component-wise egalitarian allocation of value. We show that when such strongly stable networks exist they coincide with the set of efficient networks (those maximizing the total productive value). We show that the existence of strongly stable networks is equivalent to core existence in a derived cooperative game and use that result to characterize the class of value functions for which there exist strongly stable networks via a “top convexity” condition on the value function on networks. We also consider a variation on strong stability where players can make side payments, and examine situations where value functions may be non-anonymous—depending on player labels.     

双元联盟网络如何影响突破式创新——技术能力与网络惯例的调节作用

不同类型联盟网络涉及不同程度的知识共享和知识泄露风险,并有可能对突破式创新产生差异化影响。选取合肥、南京和苏州253个企业为样本,探究企业探索性联盟网络和开发性联盟网络分别对突破式创新的直接效应,以及技术能力和网络惯例等内外部情境变量对两种关系的调节效应。结果发现：探索性联盟网络对突破式创新具有倒U型效应;开发性联盟网络对突破式创新不具有曲线效应,仅是正向线性关系;内外部不同情境变量对探索性、开发性联盟网络具有不同调节效应。其中,技术能力仅对探索性联盟网络与突破式创新间关系具有显著正向调节作用;网络惯例对开发性联盟网络与突破式创新间关系具有显著正向调节作用。研究结论对组建企业联盟和推动企业技术创新发展具有一定指导意义。     

One-way flow networks: the role of heterogeneity

I study a one-way flow connections model in which players are heterogeneous with respect to values and the costs of establishing a link. I show that values and costs heterogeneity are equally important in determining the level of connectedness and the architecture of equilibrium networks. I also show that when asymmetries are independent of the potential partner there are distributions of costs and values for which centrality is a distincitive feature of equilibrium networks. This sharply contrasts with the homogeneous case.I thank an anonymous referee for useful comments. The paper has benefited from discussion with Gabriella Conti, Jose Luis Moraga-Gonzalez, Fernando Vega-Redondo and Sanjeev Goyal.     

Evolution of networks—an experimental analysis

It is the main aim of our paper to study network formation in experimental setups in discrete and continuous time. Our design is inspired by the theoretical model on network formation by Bala and Goyal (Econometrica, 68(5): 1181–1229, 2000) as well as the experiments by Callander and Plott (J. Public Econ., 89: 1469–1495, 2005) and Falk and Kosfeld (IEW Working Paper, University of Zürich, Zürich, Switzerland, No. 146, 2003). In particular, we analyze the role of star-shaped networks which are strict Nash-equilibria of the corresponding network formation game. Our experimental results show that strict Nash networks prove to be a good indicator for predicting network formation, particularly in continuous time. In explaining our results, it turns out that, among others, the complexity in coordinating on stars, the inequity aversion against unequal payoff distribution in the network, and the groups’ degrees of activity are the most important determinants for the formation of strict Nash networks.      

Existence of Nash networks in one-way flow models

This paper addresses the existence of Nash equilibria in one-way flow models in a number of different settings. In these models players form costly links with other players and obtain resources from them through the directed path connecting them. We find that heterogeneity in the costs of establishing links plays a crucial role for the existence of Nash networks. The paper also provides conditions for the existence of Nash networks in models where costs and values of links are heterogeneous. We would like to thank an anonymous referee for useful suggestions. We would also like to thank Hans Haller and participants at the AEA Meetings 2007 for helpful comments. Sudipta Sarangi acknowledges the support of NSF grant HSD-0527315 and the hospitality of CREUSET, Jean Monnet University.     

改进的ＢＡ无标度网络模型在企业集群中的应用

各组成元素间的网络关系是企业集群的本质特征,其总体竞争力与其内部网络具有紧密联系。运用复杂网络理论研究了企业集群的无标度网络特征,并运用改进的无标度网络模型来定量分析集群网络中各构成要素的重要性,为集群向既定目标发展提供了控制依据。     

Stochastic stability and time-dependent mutations

This paper considers stochastic stability analysis in evolutionary models with time-dependent mutations. It takes a class of time-homogeneous Markov models where the transition probabilities are approximately polynomial functions of the mutation parameter and allows the mutation parameter to decline to zero over time. The main result shows that as long as the mutation parameter converges to zero slowly enough and its variation is finite, the resulting time-inhomogeneous model has a limiting distribution regardless of the details of the mutation process. Moreover, a bound on the required rate of decline is explicitly expressed as a function of the minimum coradius of the limit sets and the transition probabilities within the minimum coradius set.     

The Evolution of Social and Economic Networks

We examine the dynamic formation and stochastic evolution of networks connecting individuals. The payoff to an individual from an economic or social activity depends on the network of connections among individuals. Over time individuals form and sever links connecting themselves to other individuals based on the improvement that the resulting network offers them relative to the current network. In addition to intended changes in the network there is a small probability of unintended changes or errors. Predictions can be made regarding the likelihood that the stochastic process will lead to any given network at some time, where the stochastic process selects from among the statically stable networks and cycles. We apply these results to examples including the Gale-Shapley marriage problem. Thus the paper achieves two goals. First, it outlines a dynamic solution concept for networks. Second, it applies this concept to matching problems. Journal of Economic Literature Classification Numbers: A14, D20, J00.     

Structural stability and model design

The paper introduces the concept of structural stability and proposes that it should be considered a necessary property of scientifically valid models. Formalization of the concept is considered in both linear and non-linear models. A strong preference in favour of the wider use of non-linear models is supported by consideration of the dangers of linearization in dynamic models. The importance of structural stability is demonstrated with reference to dynamic rational expectations models which exhibit the saddle-point property. In such cases convergence to equilibrium is shown to be a structurally unstable property which can be forced by restrictive auxillary assumptions, which are highlighted.     

社会网络视角下组织间人才流动研究：相关概念、整合框架与未来展望

社会网络理论为组织基于人才流动的资源获取研究提供了全新视角与方法。然而,现有文献多集中于从社会网络结构视角探讨人才流动对企业行为与绩效的影响,而对人才流动方向、人才类型差异性,以及影响组织吸收人才资源的过程研究不足。鉴于此,在明确企业间因人才流动而形成的企业关系网络概念内涵、特征及分类的基础上,结合现有文献构建一个包含影响因素、作用机理、影响后果及情景因素等在内的整合性研究框架,并提出未来研究方向。     

Evolutionary stability and lexicographic preferences

We explore the interaction between evolutionary stability and lexicographic preferences. To do so, we define a limit Nash equilibrium for a lexicographic game as the limit of Nash equilibria of nearby games with continuous preferences. Nash equilibria of lexicographic games are limit Nash equilibria, but not conversely. Modified evolutionarily stable strategies (Binmore and Samuelson, 1992. J. Econ. Theory 57, 278–305) are limit Nash equilibria. Modified evolutionary stability differs from “lexicographic evolutionarily stability” (defined by extending the common characterization of evolutionary stability to lexicographic preferences) in the order in which limits in the payoff space and the space of invasion barriers are taken.     

制造业虚拟化转型背景下双重创新网络与创新绩效演化

制造业虚拟化转型背景下,双重创新网络的作用有待探索。运用多主体建模仿真与实证相结合的方法,考察双重创新网络对区域制造集群创新网络及其绩效的影响。结果表明：相较于区域创新绩效“缓慢—加快—稳定”的演化过程,虚拟网络嵌入后区域创新绩效呈现“加快—稳定”的特征。同时,进一步考察技术动态性对此造成的冲击,发现在不同技术动态性环境下,虚拟网络均有助于改善区域产业集群创新绩效。最后,仿真结果显示,鉴于虚拟化程度不同,创新绩效涌现出不同的变化规律,在此基础上利用南京江宁开发区制造业相关数据进行探索,发现在高技术动态条件下虚拟化程度与企业创新绩效呈倒U型关系,而低技术动态条件下呈正相关,从而为制造企业如何在虚拟化转型过程中兼顾两种异质创新网络提供一些思路。     

Candidate stability and probabilistic voting procedures

Summary. We extend the analysis of Dutta, Jackson and Le Breton (Econometrica, 2001) on strategic candidacy to probabilistic environments. For each agenda and each profile of voters preferences over running candidates, a probabilistic voting procedure selects a lottery on the set of running candidates. Assuming that candidates cannot vote, we show that random dictatorships are the only unanimous probabilistic voting procedures that never provide unilateral incentives for the candidates to withdraw their candidacy at any set of potential candidates. More flexible probabilistic voting procedures can be devised if we restrict our attention to the stability of specific sets of potential candidates.Received: 4 February 2003, Revised: 14 September 2004, JEL Classification Numbers: D71, D72.This is a revised version of a chapter of my Ph.D. Dissertation submitted to the Universitat Autónoma de Barcelona. I am indebted to my supervisor Salvador Barberá for his advice and constant support. I am grateful to Dolors Berga and an anonymous referee for their detailed comments and suggestions. I thank José Alcalde, Walter Bossert, Bhaskar Dutta, Lars Ehlers, Jordi Massó, Diego Moreno, Clara Ponsatí, Yves Sprumont, and William Thomson for many helpful comments and discussions. I thank the hospitality of the C.R.D.E. at the Université de Montréal and the Department of Economics of the University of Warwick where parts of this research were conducted. Financial support through Research Grant 1998FI00022 from Comissionat per Universitats i Recerca, Generalitat de Catalunya, Research Project PB98-870 from the Ministerio de Ciencia y Tecnología, and Fundación Barrié de la Maza is gratefully acknowledged.     

A network experiment in continuous time: The influence of link costs

In recent work on non-cooperative network formation star-shaped networks play an important role. In a particular theoretical model of Bala and Goyal (2000) center-sponsored stars are the only strict Nash networks. In testing this theoretical model, Falk and Kosfeld (2003) do not find experimental evidence that players select the center-sponsored star. Based on a slight modification of Bala and Goyal’s model, we design a network formation experiment in which, depending on link costs, periphery-sponsored stars and the empty network are the only strict Nash networks. We observe that almost all groups not only reach a strict Nash network once but also switch the center player in periphery-sponsored stars several times. The main innovation in our experiment is to use a continuous time framework which we believe to be a more realistic setting to study behavior in network formation situations and which makes coordination on stars much easier than simultaneous strategy adaptation in discrete time. Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s10683-006-9125-1. JEL Classification C72 · C92 · D81     

企业网络理论的四大流派综述

在全球化的经济环境中,企业组织结构也随着分工合作范围的扩大而突破了传统界限,这进一步深刻地影响了市场结构。在全球市场的兴起与激烈的竞争环境中,单一组织对于产品的生产越来越多地依赖外部资源,其中由合作伙伴所形成的企业间网络,日益成为组织取得外部资源最有效的方法之一,企业网络的形成是战略管理领域众多学者讨论的问题,研究学者从不同的研究视角对企业网络的形成机制做出了解释。本文在综合国内外学者对企业网络形成机制理论研究的基础上,对企业网络形成机制从资源基础学派、组织学习学派、制度经济学派、经济社会学派四个视角对其进行理论综述,深入探讨了学术界对企业网络本质认识上存在的分歧,尝试对当前企业网络理论在逻辑上做出清晰的梳理。     

Credit expansion and financial stability in Malaysia

This study investigated the degree of synchronization between credit expansion and financial stability in Malaysia at aggregated and disaggregated levels. The dynamic factor model and a broad range of macro-financial variables are adopted to construct a financial stability index to measure the stability of the Malaysian financial system. The non-parametric method is subsequently employed to gauge the degree of synchronization between credit and financial stability. The empirical findings indicated a negative synchronization between business credit and financial stability in Malaysia, suggesting that an expansion in business credit would lead to financial instability. The results implied that difficulties will arise in designing policies as business credit expands. On the other hand, there is insufficient evidence to show that increasing household credit has any negative influence on Malaysian financial stability.     

In search of stars: Network formation among heterogeneous agents

This paper reports results from a laboratory experiment on network formation among heterogeneous agents. The experimental design extends the Bala–Goyal [Bala, V., Goyal, S., 2000. A non-cooperative model of network formation, Econometrica 68, 1131–1230] model of network formation with decay and two-way flow of benefits by introducing agents with lower linking costs or higher benefits to others. Furthermore, agents' types may be common knowledge or private information. In all treatments, the (efficient) equilibrium network has a “star” structure. While equilibrium predictions fail completely with homogeneous agents, star networks frequently occur with heterogeneous agents. Stars are not born but rather develop: with a high-value agent, the network's centrality, stability, and efficiency all increase over time. A structural econometric model based on best response dynamics and other-regarding preferences is used to analyze individual linking behavior. Maximum-likelihood estimates of the underlying structural parameters, obtained by pooling data from several treatments, allow us to explain the main treatment effects.     

技术创新网络核心企业领导力影响因素研究

技术创新网络中核心企业的地位及作用一直是学者们关注的热点问题。近年来,核心企业领导力的概念逐渐引起人们的重视。在梳理技术创新网络、领导力、核心企业及核心企业领导力等相关理论研究成果的基础上,对技术创新网络核心企业领导力的内涵进行了进一步剖析和界定,运用理论探索和问卷调研方法,分析了核心企业领导力影响因素,建立了核心企业领导力影响因素概念模型,并进行了实证研究。结果表明：知识资源、网络能力、网络结构和领导者特质是影响技术创新网络核心企业领导力的主要因素。