nep-mic New Economics Papers
on Microeconomics
Issue of 2005‒09‒29
27 papers chosen by
Joao Carlos Correia Leitao
Universidade da Beira Interior

  1. Principles of Neo-Schumpeterian Economics By Horst Hanusch; Andreas Pyka
  2. A Micro-Level 'Consumer Approach' to Species Population Dynamics By Thomas Christiaans; Thomas Eichner; Rüdiger Pethig
  3. On the Uniqueness of Optimal Prices Set by Monopolistic Sellers By van den Berg, Gerard J
  4. Equilibrium and Efficiency in the Tug-of-War By Konrad, Kai A; Kovenock, Dan
  5. The Media and Advertising: A Tale of Two-Sided Markets By Anderson, Simon P; Gabszewicz, Jean Jaskold
  6. Market Definition with Differentiated Products - Lessons from the Car Market By Brenkers, Randy; Verboven, Frank
  7. Sabotage in Tournaments: Making the Beautiful Game a Bit Less Beautiful By Garicano, Luis; Palacios-Huerta, Ignacio
  8. On Noncooperative Games and Minimax Theory By Frenk, J.B.G.; Kassay, G.
  9. The Coordinate-Wise Core for Multiple-Type Housing Markets is Second-Best Incentive Compatible By Klaus,Bettina
  10. Differentiated Product Markets: An Experimental Test of Two Equilibrium Concepts By Peeters,Ronald; Strobel,Martin
  11. Bundling in Exchange Markets with Indivisible Goods By Dimitrov,Dinko; Haake,Claus-Jochen; Klaus,Bettina
  12. Monotonicity and Nash Implementation in Matching Markets with Contracts By Haake,Claus-Jochen; Klaus,Bettina
  13. Nash consistent representation of effectivity functions through lottery models By Peleg,Bezalel; Peters,Hans
  14. Spatial Cournot Oligopoly with Vertical Linkages By André Rocha; José Pedro Pontes
  15. Look How Little I’m Advertising! By Kyle Bagwell; Per Baltzer Overgaard
  16. Generalised Translation of Indirect Utility Functions By Denis Conniffe
  17. The Industrial Organization of Markets with Two-Sided Platforms By David S. Evans; Richard Schmalensee
  18. Instability in Competition: Hotelling Re-reconsidered By Helge Sanner
  19. An Axiomatic Model of Non-Bayesian Updating By Larry Epstein
  20. Price and Output Comparison under Alternative Duopoly Structures. By Jim Y. Jin; Tatiana Damjanovic; Osiris J.Parcero
  21. Embedding Consumer Taste for Location into a Structural Model of Equilibrium By Patrick Paul Walsh; Franco Mariuzzo
  22. Resolving Inconsistencies in Utility Measurement under Risk: Tests of Generalizations of Expected Utility By Han Bleichrodt; José María Abellán-Perpiñan; JoséLuis Pinto; Ildefonso Méndez-Martínez
  23. Interbank Comptetition with Costly Screening By Xavier Freixas; Sjaak Hurkens; Alan D. Morrison; Nir Vulkan
  24. Detecting Cartels By Joseph E. Harrington, Jr
  25. Competition and Innovation - Microeconometric Evidence Using Finnish Data By Juha Kilponen; Torsten Santavirta
  26. Irrationality in Consumers’ Switching Decisions: When More Firms May Mean Less Benefit By Chris M. Wilson; Catherine Waddams Price
  27. Innovators, Imitators, and the Evolving Architecture of Social Networks By Joseph E. Harrington, Jr

  1. By: Horst Hanusch (University of Augsburg, Department of Economics); Andreas Pyka (University of Augsburg, Department of Economics)
    Abstract: Within the last 25 years large progress has been made in Neo-Schumpeterian Economics, this branch of economic literature which deals with dynamic processes causing qualitative transformation of economies basically driven by the introduction of novelties in their various and multifaceted forms. By its very nature, innovation and in particular technological innovation is the most exponent and most visible form of novelty. Therefore it is not very surprising that Neo-Schumpeterian Economics today has its most prolific fields in the studies of innovation and learning behavior on the micro-level of an economy, the studies on industry dynamics on the meso-level and studies of innovation driven growth and competitiveness on the macro-level of the economy. From a general point of view, however, the future developmental potential of socio-economic systems i.e. innovation in a very broad understanding encompassing besides technological innovation also organizational, institutional and social innovation has to be considered as the normative principle of Neo-Schumpeterian Economics. In this sense, innovation plays a similar role in Neo-Schumpeterian Economics like prices do in Neoclassical Economics. Instead of allocation and efficiency within a certain set of constraints, Neo-Schumpeterian Economics is concerned with the conditions for and consequences of a removal and overcoming of these constraints limiting the scope of economic development. Thus, Neo-Schumpeterian Economics is concerned with all facets of open and uncertain developments in socio-economic systems. A comprehensive Neo-Schumpeterian approach therefore has to consider not only transformation processes going on e.g. on the industry level of an economy, but also on the public and monetary side of an economic system. Our contribution introduces those extensions and complements to a comprehensive Neo-Schumpeterian economic theory, and develops some guideposts in the sense of a roadmap for necessary strands of analysis in the future in order to fulfill the claim of becoming a comprehensive approach comparable to neoclassical theory.
    Keywords: Neo-Schumpeterian economics, industrial dynamics, public finance, financial markets
    JEL: O30 O40 L2 P0 G10 B52
    Date: 2005–09
  2. By: Thomas Christiaans; Thomas Eichner; Rüdiger Pethig
    Abstract: In this paper we develop a micro ecosystem model whose basic entities are representative organisms which behave as if maximizing their net offspring under constraints. Net offspring is increasing in prey biomass intake, declining in the loss of own biomass to predators and Allee’s Law applies. The organism’s constraint reflects its perception of how scarce its own biomass and the biomass of its prey is. In the short-run periods prices (scarcity indicators) coordinate and determine all biomass transactions and net offspring which directly translates into population growth functions. We are able to explicitly determine these growth functions for a simple food web when specific parametric net offspring functions are chosen in the micro-level ecosystem model. For the case of a single species our model is shown to yield the well-known Verhulst-Pearl logistic growth function. With two species in predator-prey relationship, we derive differential equations whose dynamics are completely characterized and turn out to be similar to the predator-prey model with Michaelis-Menten type functional response. With two species competing for a single resource we find that coexistence is a knife-edge feature confirming Tschirhart’s (2002) result in a different but related model.
    Keywords: species, growth, extinction, predator-prey relations, resource competition
    JEL: Q20
    Date: 2005
  3. By: van den Berg, Gerard J
    Abstract: This paper considers price determination by monopolistic sellers who know the distribution of valuations among the potential buyers. We derive a novel condition under which the optimal price set by the monopolist is unique. In many settings, this condition is easy to interpret, and it is valid for a very wide range of distributions of valuations. The results carry over to the optimal minimum price in independent private value auctions. In addition, they can be fruitfully applied in the analysis of quantity discount price policies.
    Keywords: auction; hazard price; hazard rate; local maxima; minimum price; monopoly; quantity discount; regularity; reservation price
    JEL: D42 D44 L12 L42
    Date: 2005–08
  4. By: Konrad, Kai A; Kovenock, Dan
    Abstract: We characterize the unique Markov perfect equilibrium of a tug-of-war without exogenous noise, in which players have the opportunity to engage in a sequence of battles in an attempt to win the war. Each battle is an all-pay auction in which the player expending the greater resources wins. In equilibrium, contest effort concentrates on at most two adjacent states of the game, the 'tipping states', which are determined by the contestants’ relative strengths, their distances to final victory, and the discount factor. In these states battle outcomes are stochastic due to endogenous randomization. Both relative strength and closeness to victory increase the probability of winning the battle at hand. Patience reduces the role of distance in determining outcomes. Applications range from politics, economics and sports, to biology, where the equilibrium behaviour finds empirical support: many species have developed mechanisms such as hierarchies or other organizational structures by which the allocation of prizes are governed by possibly repeated conflict. Our results contribute to an explanation why. Compared to a single stage conflict, such structures can reduce the overall resources that are dissipated among the group of players.
    Keywords: all-pay auction; conflict; dominance; dynamic game; multi-stage contest; preemption; tipping; winner-take-all
    JEL: D72 D74
    Date: 2005–08
  5. By: Anderson, Simon P; Gabszewicz, Jean Jaskold
    Abstract: Media industries are important drivers of popular culture. A large fraction of leisure time is devoted to radio, magazines, newspapers, the Internet, and television (the illustrative example henceforth). Most advertising expenditures are incurred for these media. They are also mainly supported by advertising revenue. Early work stressed possible market failures in program duplication and catering to the Lowest Common Denominator, indicating lack of cultural diversity and quality. The business model for most media industries is underscored by advertisers’ demand to reach prospective customers. This business model has important implications for performance in the market since viewer sovereignty is indirect. Viewers are attracted by programming, though they dislike the ads it carries, and advertisers want viewers as potential consumers. The two sides are coordinated by broadcasters (or 'platforms') that choose ad levels and program types, and advertising finances the programming. Competition for viewers of the demographics most desired by advertisers implies that programming choices will be biased towards the tastes of those with such demographics. The ability to use subscription pricing may help improve performance by catering to the tastes of those otherwise under-represented, though higher full prices tend to favour broadcasters at the expense of viewers and advertisers. If advertising demand is weak, program equilibrium program selection may be too extreme as broadcasters strive to avoid ruinous subscription price competition, but strong advertising demand may lead to strong competition for viewers and hence minimum differentiation (la pensee unique). Markets (such as newspapers) with a high proportion of ad-lovers may be served only by monopoly due to a circulation spiral: advertisers want to place ads in the paper with most readers, but readers want to buy the paper with more ads.
    Keywords: advertising finance; circulation spiral; pensee unique; platform competition; two-sided markets
    JEL: D43 L13 L82 M37 Z11
    Date: 2005–09
  6. By: Brenkers, Randy; Verboven, Frank
    Abstract: For a variety of reasons, it is likely that the market definition approach will remain an important tool in competition policy analysis for some time, despite the increased importance of other tools such as the simulation approach. Against the background of the new block exemption regulation for cars in Europe, we explore an econometric approach to define the relevant markets with differentiated products. On the one hand, the approach is directly consistent with the SSNIP-test, and it is in fact more satisfactory than previous approaches, such as critical elasticity analysis or the simple use of standard industry classifications. On the other hand, the approach shares a lot of features with the simulation approach (similar data requirements, and similar assumptions about current market power). We find that the relevant market for minivan cars is defined at the widest level, i.e. at the aggregate country level. Furthermore, in Italy the relevant markets for domestic cars are defined at an intermediate level, i.e. at the segment level. In all other cases, the relevant markets for cars may be defined at the narrowest level, i.e. at the subsegment level. Based on these results, we identify the firms that may violate the market share thresholds stipulated in the block exemption regulation. We find that, if we would have used an approach based on standard industry classifications instead of our econometric approach, our conclusions would have been different and, in fact, inconclusive. We also draw attention to other issues in market definition that may be of use to practitioners.
    Keywords: competition policy; market definition
    JEL: L4 L42
    Date: 2005–09
  7. By: Garicano, Luis; Palacios-Huerta, Ignacio
    Abstract: We exploit an incentive change in professional soccer leagues aimed at encouraging more attacking and goal scoring to obtain evidence on the effect of stronger incentives on productive and destructive effort. Using as control the behavior of the same teams in a competition that experienced no changes in incentives, we provide differences-in-differences estimates of the effect of the incentive change on the behavior of teams. We find that, although teams increased offensive effort, they also increased destructive effort (`sabotage') substantially, resulting in no net change in scoring. When ahead, teams became more conservative, increasing their defenders, scoring less goals, and allowing fewer attempts to score by their opponents. We also find that teams that engage more in sabotage activities depress the attendance at their rival's home stadiums, and that indeed attendance suffered as a result of the incentive change. Thus, teams responded to stronger incentives, but in an undesirable way.
    Keywords: incentives; multitasking; sabotage; tournaments
    JEL: D21 D82 J41 L14 M52 M55
    Date: 2005–09
  8. By: Frenk, J.B.G.; Kassay, G. (Erasmus Research Institute of Management (ERIM), RSM Erasmus University)
    Abstract: In this note we review some known minimax theorems with applications in game theory and show that these results form an equivalent chain which includes the strong separation result in finite dimensional spaces between two disjoint closed convex sets of which one is compact. By simplifying the proofs we intend to make the results more accessible to researchers not familiar with minimax or noncooperative game theory.
    Keywords: Noncooperative Game Theory;Minimax Results;
    Date: 2005–06–01
  9. By: Klaus,Bettina (METEOR)
    Abstract: We consider the generalization of Shapley and Scarf''s (1974) model of trading indivisible objects (houses) to so-called multiple-type housing markets. We show (Theorem 1) that the prominent solution for these markets, the coordinate-wise core rule, is second-best incentive compatible. In other words, there exists no other strategy-proof trading rule that Pareto dominates the coordinate-wise core rule. Given that for multiple-type housing markets Pareto efficiency, strategy-proofness, and individual rationality are not compatible, by Theorem 1 we show that applying the coordinate-wise core rule is a minimal concession with respect to Pareto efficiency while preserving strategy-proofness and individual rationality.
    Keywords: microeconomics ;
    Date: 2005
  10. By: Peeters,Ronald; Strobel,Martin (METEOR)
    Abstract: In markets with differentiated products Bertrand-Nash equilibria in pure strategies may not exist. Mixed strategies are difficult to calculate. For these cases Morgan and Shy (2000) suggest an alternative solution concept, the undercut-proof equilibrium (UPE). While the Nash-equilibrium is motivated by the question of how ones own behavior influences one''s payoff, the UPE is motivated by the question of how others'' behavior influence one''s payoff. We report on an experiment where we test these two concepts with respect to their comparative statics. Moreover we investigate the nature of subjects'' underlying thinking process. Our results provide strong evidence against the UPE and in favor of Bertrand-Nash.
    Keywords: microeconomics ;
    Date: 2005
  11. By: Dimitrov,Dinko; Haake,Claus-Jochen; Klaus,Bettina (METEOR)
    Abstract: We study efficient and individually rational exchange rules for markets with heterogeneous indivisible goods that exclude the possibility that an agent benefits by bundling goods in her endowment. Even if agents'' preferences are additive, no such rule exists.
    Keywords: microeconomics ;
    Date: 2005
  12. By: Haake,Claus-Jochen; Klaus,Bettina (METEOR)
    Abstract: We consider general two-sided matching markets, so-called matching with contracts markets as introduced by Hatfield and Milgrom (2005), and analyze (Maskin) monotonic and Nash implementable solutions. We show that for matching with contracts markets the stable correspondence is monotonic and implementable (Theorems 1 and 3). Furthermore, any solution that is Pareto efficient, individually rational, and monotonic is a supersolution of the stable correspondence (Theore m 2). In other words, the stable correspondence is the minimal solution that is Pareto efficient, individually rational, and implementable.
    Keywords: microeconomics ;
    Date: 2005
  13. By: Peleg,Bezalel; Peters,Hans (METEOR)
    Abstract: Effectivity functions for finitely many players and alternatives are considered. It is shown that every monotonic and superadditive effectivity function can be augmented with equalchance lotteries to a finite lottery model---i.e., an effectivity function that preserves the original effectivity in terms of supports of lotteries---which has a Nash consistentrepresentation. In other words, there exists a finite game form which represents the lottery model and which has a Nash equilibrium for any profile of utility functions, where lotteriesare evaluated by their expected utility. No additional condition on the original effectivity function is needed.
    Keywords: microeconomics ;
    Date: 2005
  14. By: André Rocha; José Pedro Pontes
    Abstract: This paper examines the equilibrium of location of N vertically-linked firms. In a spatial economy composed of two regions, a monopolist firm supplies an input to N consumer goods firms that compete in quantities. It was concluded that, when there are increases in the transport cost of the input, downstream firms prefer to agglomerate in the region where the upstream firm is located, in order to obtain savings in the production cost. On the other hand, increases in the general transport cost or in the number of downstream firms lead to a dispersion of these firms, in order to reduce competition and locate closer to the final consumer.
    Keywords: Agglomeration; Intermediate Goods; Spatial Oligopoly.
    JEL: R30 L13 C72
  15. By: Kyle Bagwell (Department of Economics, Columbia University); Per Baltzer Overgaard (School of Economics and Management, University of Aarhus)
    Abstract: This paper studies the role of advertising and prices as signals of quality in a purely static setting, where repeat purchases are suppressed altogether, but where advertising affects demand directly. We first show, under standard regularity assumptions, that the high-quality firm will distort its price upwards and its level of advertising downwards compared to the complete-information case. We then show, under relatively mild additional conditions, that the high-quality firm will choose a level of advertising below that of the low-quality firm, even if the high-quality firm advertises most under complete information. Hence, empirically, a high price and a modest advertising budget may well signal high quality.
    Keywords: quality; signaling; pricing; advertising
    JEL: D82 L15 M37
    Date: 2005–09
  16. By: Denis Conniffe (Economics Department, National University of Ireland, Maynooth, Co. Kildare, Ireland.)
    Abstract: This paper considers the derivation of new demand systems from existing ones through replacing an indirect utility function ) , ( y U p by } ) / ( , { j y p y y U j j â ã Ó . p , where p is a vector of prices and y is income. This is a generalisation of Gorman translation ) , ( j j p y U ã Ó . p and will be shown to be effective in terms of producing new demand systems with both good regularity and flexibility properties.
    Keywords: Translation,indirect utility functions,demand equations
    JEL: D11
    Date: 2004–08
  17. By: David S. Evans; Richard Schmalensee
    Abstract: Two-sided platforms (2SPs) cater to two or more distinct groups of customers, facilitating value-creating interactions between them. The village market and the village matchmaker were 2SPs; eBay and are more recent examples. Other examples include payment card systems, magazines, shopping malls, and personal computer operating systems. Building on the seminal work of Rochet and Tirole (2003), a rapidly growing literature has illuminated the economic principles that apply to 2SPs generally. One key result is that 2SPs may find it profit-maximizing to charge prices for one customer group that are below marginal cost or even negative, and such skewed pricing pattern is prevalent, although not universal, in industries that appear to be based on 2SPs. Over the years, courts have also recognized that certain industries, notably payment card systems and newspapers, now understood to be based on 2SPs, are governed by unusual economic relationships. This chapter provides an introduction to the economics of 2SPs and its application to several competition policy issues.
    JEL: D4 L1 L4
    Date: 2005–09
  18. By: Helge Sanner
    Abstract: In this paper we show that Puu (2002) does not provide a stable solution to the location game, according to his own definition of stability. If the usual two-stage game is considered, where in the first stage a location is chosen once and forever, and in the second stage prices are determined, the equilibrium proves stable for a sizeable interval of parameters, however. Even though this procedure is most common in analyzing Hotelling's location problem, it is not satisfying because it exhibits an inconsistent informational structure. The search for a better concept of stability is imperative.
    Keywords: Hotelling's main street; Instability of equilibrium
    JEL: D43 L11 L13 R30
    Date: 2005–09
  19. By: Larry Epstein (University of Rochester)
    Abstract: This paper models an agent in a three-period setting who does not update according to Bayes'Rule, and who is self-aware and anticipates her updating behavior when formulating plans. The agent is rational in the sense that her dynamic behavior is derived from a single stable preference order on a domain of state-contingent menus of acts. A representation theorem generalizes the (dynamic version of) Anscombe-Aumann's theorem so that both the prior and the way in which it is updated are subjective.
    Keywords: Bayes' Rule, non-Bayesian updating, asset price volatility, no-trade theorems, agreeing to bet, common knowledge, temptation, self-control, conservatism, representativeness, overconfidence
    JEL: D81 D83 D9
    Date: 2005–09
  20. By: Jim Y. Jin; Tatiana Damjanovic; Osiris J.Parcero
    Abstract: Duopoly competition can take different forms: Bertrand, Cournot, Bertrand-Stackelberg, Cournot-Stackelberg and joint profit maximization. In this paper we find a clear price ranking among these five markets when goods are substitutes and an output ranking when goods are complements. Moreover, the ranking can be explained by different levels of conjectural variation associated with those markets.
    Keywords: Bertrand, Cournot, Stackelberg, monopoly, ranking, conjectural variation
    JEL: L11 L13 D43
    Date: 2005–09
  21. By: Patrick Paul Walsh; Franco Mariuzzo (Department of Economics, Trinity College)
    Abstract: Given that brands (products) are location specific in terms of coverage of retail stores, we allow consumers to have preferences over location and products to carry distribution costs, alongside preferences and costs over other observable and unobservable product characteristics. We embed these considerations into Berry, Levinsohn and Pakes (1995) to jointly estimate demand and cost parameters for brands (products) in Retail Carbonated Soft Drinks. Allowing for location has a very significant impact on estimated primitives and the predictive power of the structural model. As a counterfactual exercise we show the e?ects on welfare of an equilibrium that results from a change in the distribution of consumer taste for location.
    JEL: L11 L62
    Date: 2005–08
  22. By: Han Bleichrodt; José María Abellán-Perpiñan; JoséLuis Pinto; Ildefonso Méndez-Martínez
    Abstract: This paper explores biases in the elicitation of utilities under risk and the contribution that generalizations of expected utility can make to the resolution of these biases. We used five methods to measure utilities under risk and found clear violations of expected utility. Of the theories studies, prospect theory was most consistent with our data. The main improvement of prospect theory over expected utility was in comparisons between a riskless and a risky prospect(riskless-risk methods). We observed no improvement over expected utility in comparisons between two risky prospects (risk-risk methods). An explanation why we found no improvement of prospect theory over expected utility in risk-risk methods may be that there was less overweighting of small probabilities in our study than has commonly been observed.
    Keywords: Utility Measurement, Nonexpected Utility, Prospect Theory, Health.
    JEL: D81 I10
    Date: 2005–01
  23. By: Xavier Freixas; Sjaak Hurkens; Alan D. Morrison; Nir Vulkan
    Abstract: We analyse credit market equilibrium when banks screen loan applicants. When banks have a convex cost function of screening, a pure strategy equilibrium exists where banks optimally set interest rates at the same level as their competitors. This result complements Broecker’s (1990) analysis, where he demonstrates that no pure strategy equilibrium exists when banks have zero screening costs. In our set up we show that interest rate on loans are largely independent of marginal costs, a feature consistent with the extant empirical evidence. In equilibrium, banks make positive profits in our model in spite of the threat of entry by inactive banks. Moreover, an increase in the number of active banks increases credit risk and so does not improve credit market effciency: this point has important regulatory implications. Finally, we extend our analysis to the case where banks have differing screening abilities.
    Keywords: Interbank Competition, Screening, Credit Risk, Adverse Selection
    JEL: D43 D82 G21 G24
    Date: 2004–11
  24. By: Joseph E. Harrington, Jr
    Abstract: In reviewing the theoretical and empirical literature on collusion, this paper distills methods for detecting cartels and distinguishing collusion from competition.
    Date: 2005–07
  25. By: Juha Kilponen (Bank of Finland); Torsten Santavirta (University of Helsinki)
    Abstract: In this study we provide a theoretical prediction of a complementary relationship between the incentive effects of product market competition and R&D subsidies using the theory of Aghion et. al (1997, 2001). The complementarity relationship and that of an inverted U-relationship is then tested using a large Finnish firm level data set combined with patent and patent citations of the firms. Econometric analysis shows that the inverted U-relationship is fairly robust to different innovation measures derived from patent data. We also find that the inverted-U relationship tends to be steeper when also R&D subsidies are considered. This result suggests that there exists a complementarity between competition and R&D subsidies.
    Keywords: Product market competition, Innovations, R&D subsidies
    JEL: L
    Date: 2005–09–16
  26. By: Chris M. Wilson (University of East Anglia); Catherine Waddams Price (University of East Anglia)
    Abstract: We report evidence of three types of consumer switching decision errors within the UK electricity market. We identify consumers who do not switch despite substantial available savings, consumers who switch from a cheaper to a more expensive supplier and consumers who switch to a cheaper, but not the cheapest available supplier. Moreover, we find that consumers make more efficient decisions in markets with fewer competitors. This finding is consistent with theories of consumer confusion and “information-overload” rather than other “rational” explanations of consumer mistakes such as perceived differences in firm quality or uncertainty over consumers’ own demand.
    Keywords: Consumer choice, Switching costs, Behavioural IO
    JEL: L00 D12
    Date: 2005–09–20
  27. By: Joseph E. Harrington, Jr
    Abstract: Scientific progress is driven by innovation — which serves to produce a diversity of ideas — and imitation through a social network — which serves to diffuse these ideas. In this paper, we develop an agent-based computational model of this process, in which the agents in the population are heterogeneous in their abilities to innovate and imitate. The model incorporates three primary forces — the discovery of new ideas by those with superior abilities to innovate, the observation and adoption of these ideas by those with superior abilities to communicate and imitate, and the endogenous development of social networks among heterogeneous agents. The objective is to explore the evolving architecture of social networks and the critical roles that the innovators and imitators play in the process. A central finding is that the emergent social network takes a chainstructure with the innovators as the main source of ideas and the imitators as the connectors between the innovators and the masses. The impact of agent heterogeneity and environmental volatility on the network architecture is also characterized.
    Date: 2005–09

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