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on Network Economics |
| By: | Timo Hiller (European University Institute) |
| Abstract: | This paper presents a game-theoretic model of network formation, which allows agents to enter bilateral alliances and to extract payoffs from enemies. Each pair of agents creates a surplus of one, which allies divide in equal parts. If agents are enemies, then the agent with more allies obtains a larger share of the surplus. I show that Nash equilibria are of two types. First, a state of utopia, where all agents are allies. Second, asymmetric equilibria, such that agents can be partitioned into sets of different size, where agents within the same set are allies and agents in different sets are enemies. These results stand in contrast to coalition formation games in the economics of conflict literature, where stable group structures are generally symmetric. The model provides a game-theoretic foundation for structural balance, a long- standing notion in social psychology, which has been fruitfully applied to the study of alliance formation in international relations. |
| Keywords: | Network Formation, Economics of Conflict, Contest Success Function, Structural Balance, International Relations |
| JEL: | D86 D74 |
| Date: | 2011–06 |
| URL: | http://d.repec.org/n?u=RePEc:fem:femwpa:2011.42&r=net |
| By: | Sunghoon Hong (Vanderbilt University) |
| Abstract: | We develop a strategic model of network interdiction in a non-cooperative game of flow. An adversary, endowed with a bounded quantity of bads, chooses a flow specifying a plan for carrying bads through a network from a base to a target. Simultaneously, an agency chooses a blockage specifying a plan for blocking the transport of bads through arcs in the network. The bads carried to the target cause a target loss while the blocked arcs cause a network loss. The adversary earns and the agency loses from both target loss and network loss. The adversary incurs the expense of carrying bads. In this model we study Nash equilibria and find a power law relation between the probability and the extent of the target loss. Our model contributes to the literature of game theory by introducing non-cooperative behavior into a Kalai-Zemel (cooperative) game of flow. Our research also advances models and results on network interdiction. |
| Keywords: | Network Interdiction, Noncooperative Game of Flow, Nash Equilibrium, Power Law, Kalai-Zemel Game of Flow |
| JEL: | C72 D85 H56 |
| Date: | 2011–06 |
| URL: | http://d.repec.org/n?u=RePEc:fem:femwpa:2011.43&r=net |
| By: | Galina Hale |
| Abstract: | Recent literature argues that the structure of a banking network is important for its stability. We use network analysis to formally describe bank relationships in the global banking network between 1980 and 2009 and analyze the effects of recessions and banking crises on these relationships. We construct a novel data set that builds a bank-level global network from loan-level data on syndicated loans to financial institutions. Our network consists of 7938 banking institutions from 141 countries. We find that the network became more interconnected and more asymmetric, and therefore potentially more fragile, prior to 2008, and that its expansion slowed in recent years, dramatically so during the 2008-09 crisis. We use a stylized model to describe potential effects of banking crises and recessions on bank relationships. Empirically, we find that the structure of a global banking network is not invariant to banking crises nor to recessions, especially those in the United States. While recessions appear to encourage banks to make new connections, especially on the periphery of the network, the global financial crisis of 2008-09 made banks very cautious in their lending, meaning that almost no new connections were made during the crisis, particularly in 2009. We also find that during country-specific recessions or banking crises past relationships become more important as few new relationships are formed. |
| Keywords: | Banks and banking ; Financial crises |
| Date: | 2011 |
| URL: | http://d.repec.org/n?u=RePEc:fip:fedfwp:2011-14&r=net |
| By: | G. Camera; M. Casari |
| Abstract: | Under what conditions can cooperation be sustained in a network of strangers? Here we study the role of institutions and uncover a new behavioral foundation for the use of monetary systems. In an experiment, anonymous subjects could cooperate or defect in bilateral random encounters. This sequence of encounters was indefinite; hence multiple equilibria were possible, including full intertemporal cooperation supported by a social norm based on community punishment of defectors. We report that such social norm did not emerge. Instead, the availability of intrinsically worthless tokens favored the coordination on intertemporal cooperation in ways that networks of strangers were unable to achieve through social norms. |
| JEL: | C90 C70 D80 |
| Date: | 2011–05 |
| URL: | http://d.repec.org/n?u=RePEc:bol:bodewp:wp754&r=net |
| By: | Julia Belau |
| Abstract: | In this paper, I introduce an extension of (TU) games with a coalition structure. Taking a situation where all coalitions are already established is not reasonable in order to forecast the reality; there is not only one possible coalition, there are several. I consider situations where coalitions are not established yet and take into account the likelihood of each possible coalition. This leads to a generalized, probabilistic setting for coalition structures. Probabilistic versions of known axioms are introduced as well as new probabilistic axioms. Generalizations of both the outside-option-sensitive chi-value (Casajus, Soc Choice Welf 32, 1-13, 2009) and its outside-option-insensitive pendant, the component restricted Shapley value (Aumann and Drèze, Int. J. Game Theory 3, 217-237, 1974), are defined and axiomatic characterizations are given. |
| Keywords: | TU game; coalition structure; outside option |
| JEL: | C71 |
| Date: | 2011–01 |
| URL: | http://d.repec.org/n?u=RePEc:rwi:repape:0236&r=net |