This paper proposes new centrality measures to characterise the 'key class', when agents in a network are sorted into … role-equivalent classes, such that its removal results in an optimal change in the network activity. The notion of role …-equivalence is defined through the graph-theoretical concept of equitable partition of networks, which finds wide empirical and …

We develop a model of contests on networks. Each player is “connected” to a set of contests and exerts a single effort … many well-known results from the contest literature can be obtained by varying the structure of the network. Our framework …

neighbors in the social network. The same activities often exert externalities that cumulate in "stocks" affecting agents … network of social relations, as agents display strategic substitution with distance-two neighbors. We show that behavior is … behavior and key-players tend to move to the periphery of the network, and we discuss the effect of close-knit communities and …