We study a coordination game among agents in a network. The agents choose whether to take action (e.g. adopting a new technology) in an uncertain environment that yields increasing value in the actions of neighbours. We develop an algorithm that fully partitions the network into communities (coordination sets) within which agents have the same propensity to adopt. Our main finding is that a novel measure of network connectedness, which we term “social connectedness,” determines the propensity to adopt for each agent. Social connectedness captures both the number of links each agent has within her community (interconnectedness) as well as the number of links she has with members of other communities who have a higher propensity to adopt (embeddedness). There is a single coordination set if and only if the network is balanced—that is, the average degree of each subnetwork is no larger than the average degree of the network. Finally, we demonstrate that contagion is localized within coordination sets, such that a shock to an agent uniformly affects this agent and all members of her coordination set but has no impact on the other agents in the network.

中文翻译：

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社会联系和地方传染

我们研究了网络中代理之间的协调博弈。代理人选择是否在一个不确定的环境中采取行动（例如采用新技术），这会在邻居的行动中产生越来越大的价值。我们开发了一种算法，将网络完全划分为社区（协调集），在这些社区中，代理具有相同的采用倾向。我们的主要发现是一种新的网络连通性度量，我们称之为“社会连通性”，它决定了每个代理采用的倾向。社会联系既捕捉了每个代理人在她的社区中拥有的链接数量（互连性），也捕捉了她与其他社区成员之间的链接数量，这些成员具有更高的采用倾向（嵌入性）。当且仅当网络平衡时，才会有一个协调集——也就是说，每个子网的平均度不大于网络的平均度。最后，我们证明传染是在协调集中定位的，因此对代理的冲击会统一影响该代理及其协调集中的所有成员，但对网络中的其他代理没有影响。