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Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. The question how to optimally design an infrastructure network that may be subject to intelligent threats is of highest interest. We address this problem by considering a Designer-Adversary game of optimal network design for the case of imperfect node defense. In this two-stage game, first the Designer defends network connectivity by forming costly links and additionally protecting nodes. Then, the Adversary attacks a fixed number of nodes, aiming to disconnect the network. In contrast to the existing literature, defense is imperfect in the sense that defended nodes can still be destroyed with some fixed probability. We completely characterize the solution of the game for attack budgets of one and two nodes, while for larger budget we present a partial characterization of the solution. To do so, we determine the minimum number of links necessary to construct a network with any degree of connectivity and any given number of essential nodes. Terms of use: Documents in

We propose a random network model incorporating heterogeneity of agents and a continuous notion of homophily. Unlike the vast majority of the corresponding economic literature, we capture homophily in terms of similarity rather than equality of agents. We show that if links between similar agents are indeed more likely, our homophilous random network model exhibits clustering. Moreover, simulations indicate that the well-known small-world phenomenon is preserved even at high homophily levels. As a possible application we provide a stylized labor market model, where a firm can hire a worker via the social network.

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