nep-net New Economics Papers
on Network Economics
Issue of 2009‒02‒28
seven papers chosen by
Yi-Nung Yang
Chung Yuan Christian University

  1. Tying, Compatibility and Planned Obsolescence By Miao, Chun-Hui
  2. Endogenous Network Dynamics By Frank H. Page, Jr., Myrna H. Wooders
  3. Acceptable Risk in a Portfolio Analysis By Steinbacher, Matjaz
  4. Club Networks with Multiple Memberships and Noncooperative Stability By Frank H. Page, Jr., Myrna H. Wooders
  5. Peer Effects and Social Networks in Education By Calvó-Armengol, Antoni; Patacchini, Eleonora; Zenou, Yves
  6. The Role of Liquidity Individuals in the Decision-Making By Steinbacher, Matjaz
  7. Knowledge, Preferences and Shocks in Portfolio Analysis By Steinbacher, Matjaz

  1. By: Miao, Chun-Hui
    Abstract: According to the hypothesis of planned obsolescence, a durable goods monopolist without commitment power has an excessive incentive to introduce new products that make old units obsolete, and this reduces its overall profitability. In this paper, I reconsider the above hypothesis by examining the role of competition in a monopolist's upgrade decision. I find that, when a system add-on is competitively supplied, a monopolist chooses to tie the add-on to a new system that is only backward compatible, even if a commitment of not introducing the new system is available and socially optimal. Tying facilitates a price squeeze.
    Keywords: Compatibility; Durable Goods; Network Externalities; Planned Obsolescence; Tying.
    JEL: L12 L40
    Date: 2008–12–31
  2. By: Frank H. Page, Jr., Myrna H. Wooders (Indiana University Bloomington Vanderbilt University)
    Abstract: In all social and economic interactions, individuals or coalitions choose not only with whom to interact but how to interact, and over time both the structure (the “with whom”) and the strategy (“the how”) of interactions change. Our objectives here are to model the structure and strategy of interactions prevailing at any point in time as a directed network and to address the following open question in the theory of social and economic network formation: given the rules of network and coalition formation, the preferences of individuals over networks, the strategic behavior of coalitions in forming networks, and the trembles of nature, what network and coalitional dynamics are likely to emergence and persist. Our main contributions are (i) to formulate the problem of network and coalition formation as a dynamic, stochastic game, (ii) to show that this game possesses a stationary correlated equilibrium (in network and coalition formation strategies), (iii) to show that, together with the trembles of nature, this stationary correlated equilibrium determines an equilibrium Markov process of network and coalition formation which respects the rules of network and coalition formation and the preferences of individuals, and (iv) to show that, although uncountably many networks may form, this endogenous process of network and coalition formation possesses a nonempty finite set of ergodic measures and generates a finite, disjoint collection of nonempty subsets of networks and coalitions, each constituting a basin of attraction. Moreover, we extend to the setting of endogenous Markov dynamics the notions of pairwise stability (Jackson-Wolinsky, 1996), strong stability (Jackson-van den Nouweland, 2005), and Nash stability (Bala-Goyal, 2000), and we show that in order for any network-coalition pair to be stable (pairwise, strong, or Nash) it is necessary and sufficient that the pair reside in one of finitely many basins of attraction - and hence reside in the support of an ergodic measure. The results we obtain here for endogenous network dynamics and stochastic basins of attraction are the dynamic analogs of our earlier results on endogenous network formation and strategic basins of attraction in static, abstract games of network formation (Page and Wooders, 2008), and build on the seminal contributions of Jackson and Watts (2002), Konishi and Ray (2003), and Dutta, Ghosal, and Ray (2005).
    Date: 2009–02
  3. By: Steinbacher, Matjaz
    Abstract: A social network has been used to simulate how agents of different levels of risk aversion under different circumstances behave in financial markets when deciding between risk-free and a risky asset. This is done by a discrete time version evolutionary game of risk-loving and risk-averse agents. The evolutionary process takes place on a social network through which investors acquire information they need to choose the strategy. A significant feature of the paper is that first-order stochastic dominance is a key determinant of the decision-making, while second-order stochastic dominance is not, with the level of omniscience and preferences of agents also having a significant role. Under most of the circumstances, pure risk-aversion turns out to be dominated strategy, while pure risk-taking “almost” dominant.
    Keywords: social networks; portfolio analysis; stochastic finance; stochastic dominance
    JEL: G11 Z13 C73
    Date: 2009
  4. By: Frank H. Page, Jr., Myrna H. Wooders (Indiana University Bloomington Vanderbilt University)
    Abstract: Modeling club structures as bipartite directed networks, we formulate the problem of club formation as a noncooperative game of network formation and identify conditions on network formation rules and players’ network payoffs sufficient to guarantee that the game has a potential function. Our sufficient conditions on network formation rules require that each player be choose freely and unilaterally those clubs he joins and also his activities within these clubs (subject to his set of feasible actions). We refer to our conditions on rules as noncooperative free mobility. We also require that players’ payoffs be additively separable in player-specific payoffs and externalities (additive separability) and that payoff externalities — a function of club membership, club activities, and crowding — be identical across players (externality homogeneity). We then show that under these conditions, the noncooperative game of club network formation is a potential game over directed club networks and we discuss the implications of this result.
    Date: 2009–02
  5. By: Calvó-Armengol, Antoni; Patacchini, Eleonora; Zenou, Yves
    Abstract: This paper studies whether structural properties of friendship networks affect individual outcomes in education. We first develop a model that shows that, at the Nash equilibrium, the outcome of each individual embedded in a network is proportional to her Katz-Bonacich centrality measure. This measure takes into account both direct and indirect friends of each individual but puts less weight to her distant friends. We then bring the model to the data by using a very detailed dataset of adolescent friendship networks. We show that, after controlling for observable individual characteristics and unobservable network specific factors, the individual's position in a network (as measured by her Katz-Bonacich centrality) is a key determinant of her level of activity. A standard deviation increase in the Katz-Bonacich centrality increases the pupil school performance by more than 7 percent of one standard deviation.
    Keywords: centrality measure; network structure; peer influence; school performance
    JEL: A14 C31 C72
    Date: 2008–11
  6. By: Steinbacher, Matjaz
    Abstract: We simulate social network games of a portfolio selection to analyze the role of liquidity individuals for the developments in individuals’ decision-making in financial markets. Liquidity individuals prove to be a significant element in the decision-making process of the entire network, as they keep the information of non-dominant strategies alive. Their role is especially significant under omniscient individuals, whereas a little less under non-omniscient individuals. As long as individuals do not lose the information of all the alternatives, their role is insignificant.
    Keywords: social networks; portfolio analysis; stochastic finance
    JEL: G11 Z13 C73
    Date: 2009
  7. By: Steinbacher, Matjaz
    Abstract: We simulate social network games of a portfolio selection to analyze how knowledge, preferences of agents and their level of omniscience affect their decision-making. The key feature of the paper is that preferences and the level of omniscience of agents very much determine the ways agents make their decision. While omniscient agents respond very rapidly to the changing market conditions, non-omniscient agents are more resistant to such changes. By introducing one-time shock, we found that its efficiency depends on the level of omniscience of agents, with much stronger efficiency under omniscient agents.
    Keywords: social networks; stochastic finance; shocks; portfolio analysis
    JEL: G11 Z13 C73
    Date: 2009

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