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on Network Economics |
| By: | Banerji, A (Delhi School of Economics, University of Delhi); Dutta, Bhaskar (Department of Economics, University of Warwick,) |
| Abstract: | This paper models interaction between groups of agents by means of a graph where each node represents a group of agents and an arc represents bilateral interaction. It departs from the standard Katz-Shapiro framework by assuming that network benefits are restricted only amongst groups of linked agents. It shows that even if rival firms engage in Bertrand competition, this form of network externalities permits strong market segmentation in which firms divide up the market and earn positive profits. The analysis also shows that some graphs or network structures do not permit such segmentation, while for others, there are easy to interpret conditions under which market segmentation obtains in equilibrium |
| Keywords: | network structure ; network externalities ; price competition ; market segmentation |
| JEL: | D7 |
| Date: | 2005 |
| URL: | http://d.repec.org/n?u=RePEc:wrk:warwec:725&r=net |
| By: | Pierre-Philippe Combes; Laurent Linnemer; Michael Visser |
| Abstract: | This paper analyzes the determinants of success at the concours d'agrégation en sciences économiques. This is a centralized hiring procedure through which professors of economics are selected in France. Using detailed data from all concours held between 1984 and 2003, we focus on the role of the candidates' publication records (number and quality of scientific articles) and networks (defined as professional links between candidates and the jury members who take the recruitment decisions). Both sets of variables have statistically significant effects on the likelihood of getting hired. The effect of network connections is important in the sense that a substantial improvement of the publication record is needed to compensate for not being linked to the jury. |
| Keywords: | Employment ; Hiring; Professional network |
| JEL: | M51 |
| Date: | 2006–05 |
| URL: | http://d.repec.org/n?u=RePEc:lea:leawpi:0604&r=net |
| By: | Fabio Manenti (University of Padua); Paolo Lupi (Autorita' per le garanzie nelle comunicazioni (Italy)) |
| Abstract: | Despite a general trend of lower charges for mobile calls, prices for international roaming calls have remained at levels surprisingly high. The apparent reluctance of European mobile network operators to lower roaming tariffs is generating many antitrust concerns. This paper discusses in a two country - two firm framework, the distortions associated with the functioning of the current system governing wholesale international roaming agreements based on Inter Operator Tariffs (IOTs) and the role played by cross border roaming alliances between foreign operators. We describe how competition between roaming operators at the wholesale level is influenced by the adoption of traffic redirection techniques. The paper shows that when mobile operators act un-cooperatively and traffic redirection techniques allow only partial control on traffic flows, competition between roaming operators may not guarantee a reduction in IOTs and, consequently, on retail tariffs. We propose a simple and effective regulatory price cap mechanism to restore efficiency in the wholesale market. When mobile operators cooperate within a cross border alliance, internal IOTs are set at cost and retail prices are lower. |
| JEL: | L13 L51 L42 L96 |
| Date: | 2006–05 |
| URL: | http://d.repec.org/n?u=RePEc:pad:wpaper:0019&r=net |
| By: | Rattanasuda Poolsombat; Gianluigi Vernasca |
| Abstract: | In this paper we explore the possibility of "partial-multihoming" in a two-sided market where a subset of agents, on one or both side(s), may multihome in equilibrium. We consider a model in which platforms are spatially differentiated and on each side of the market there are two type of agents, low type and high type agents, that differ only by their preferences over the network benefits. We derive under which conditions of network preferences, an equilibrium with partial multihoming on both sides exists. We show that for such an equilibrium to exist, the network benefits of high type agents must be sufficiently higher than transportation costs. Furthermore, the proportions of agents who multihome on both sides must be sufficiently small. Finally, we show that independently of the degree of multihoming on the other side of the market, agents in each group face higher prices when there is partial multihoming on their side than when there is singlehoming. |
| Keywords: | Two-sided markets, network externalities, heterogeneous agents. |
| JEL: | L13 |
| Date: | 2006–06 |
| URL: | http://d.repec.org/n?u=RePEc:yor:yorken:06/10&r=net |
| By: | Page Jr, Frank H (Department of Finance, University of Alabama); Wooders, Myrna H (Department of Economics, Vanderbilt University and Department of Economics, University of Warwick) |
| Abstract: | We make four main contributions to the theory of network formation. (1) The problem of network formation with farsighted agents can be formulated as an abstract network formation game. (2) In any farsighted network formation game the feasible set of networks contains a unique, finite, disjoint collection of nonempty subsets having the property that each subset forms a strategic basin of attraction. These basins of attraction contain all the networks that are likely to emerge and persist if individuals behave farsightedly in playing the network formation game. (3) A von Neumann Morgenstern stable set of the farsighted network formation game is constructed by selecting one network from each basin of attraction. We refer to any such von Neumann-Morgenstern stable set as a farsighted basis. (4) The core of the farsighted network formation game is constructed by selecting one network from each basin of attraction containing a single network. We call this notion of the core, the farsighted core. We conclude that the farsighted core is nonempty if and only if there exists at least one farsighted basin of attraction containing a single network. To relate our three equilibrium and stability notions (basins of attraction, farsighted basis, and farsighted core) to recent work by Jackson and Wolinsky (1996), we define a notion of pairwise stability similar to the Jackson-Wolinsky notion and we show that the farsighted core is contained in the set of pairwise stable networks. Finally, we introduce, via an example, competitive contracting networks and highlight how the analysis of these networks requires the new features of our network formation model. |
| Keywords: | Basins of attraction ; Network formation ; Supernetworks ; Farsighted core ; Nash networks |
| JEL: | A14 D20 J00 |
| Date: | 2005 |
| URL: | http://d.repec.org/n?u=RePEc:wrk:warwec:724&r=net |
| By: | Bloch, Francis (GREQAM, Universite d Aix-Marseille,); Dutta, Bhaskar (Department of Economics, University of Warwick) |
| Abstract: | This paper analyzes the formation of communication networks when players choose endogenously their investment on communication links. We consider two alternative de?nitions of network reliability ; product reliability, where the decay of information depends on the product of the strength of communication links, and min reliability where the speed of connection is a¤ected by the weakest communication link. When investments are separable, the architecture of the efficient network depends crucially on the shape of the transformation function linking investments to the quality of communication links. With increasing marginal returns to investment, the efficient network is a star ; with decreasing marginal returns, the con?ict between maximization of direct and indirect bene?ts prevents a complete characterization of efficient networks. However, with min reliability, the efficient network must be a tree. Furthermore, in the particular case of linear transformation functions, in an e¢ cient network, all links must have equal strength. When investments are perfect complements, the results change drastically : under product reliability, the efficient network must contain a cycle, and is in fact a circle for small societies. With min reliability, the e¢ cient network is either a circle or a line. As in classical models of network formation, e fficient networks may not be supported by private invesment decisions. We provide examples to show that the star may not be stable when the transformation functions is strictly convex. We also note that with perfect substitutes and perfect complements (when the e¢ cient network displays a very symmetric structure), the e¢ cient network can indeed be supported by private investments when the society is large. |
| Keywords: | communication networks ; network reliability |
| JEL: | D85 C70 |
| Date: | 2005 |
| URL: | http://d.repec.org/n?u=RePEc:wrk:warwec:723&r=net |
| By: | M. MEULEMAN; S. MANIGART; A. LOCKETT; M. WRIGHT |
| Abstract: | While one stream of research in partner selection has emphasized stability in a firm’s social network, another stream has emphasized the need to expand a firm’s network. In order to reconcile these two perspectives, we explore transaction, partner and macro conditions that lead firms to work with unfamiliar partners. Using a unique hand-collected dataset, results from the formation of private equity investment syndicates demonstrate that firms are more likely to select unfamiliar partners for lower levels of primary and behavioral uncertainty and higher levels of competition. Our findings provide insights in conditions that lead firms to expand their social network. |
| Date: | 2006–03 |
| URL: | http://d.repec.org/n?u=RePEc:rug:rugwps:06/371&r=net |