We examine the spread of a disease or behavior through a social network. In particular, we analyze how infection rates depend on the distribution of degrees (numbers of links) among the nodes in the network. We introduce new techniques using …rstand second order stochastic dominance relationships of the degree distribution in order to compare infection rates across di¤erent social networks. JEL...

We analyze a team formation process that generalizes matching models and network formation models, allowing for overlapping teams of heterogeneous size. We define a weak concept of stability, called myopic team-wise stability, which extends to our setup the concept of pair-wise stability used in network formation models. Then we refine it in two ways: (i) through stochastic stability, where age...

This paper provides a theory of endogenous network formation in over-the-counter markets based on trade competition and inventory risk balancing. A core-periphery network structure arises as an equilibrium outcome. A small number of agents emerge as core dealers to intermediate among a large number of peripheral agents. The equilibrium level of dealer entry (the size of the core) depends on the...

We introduce a simple two-stage game of endogenous network formation and information sharing for reasoning about the optimal design of social networks like Facebook or Google+. We distinguish between unilateral and bilateral connections and between targeted and collective information sharing. Agents value being connected to other agents and sharing and receiving information. We consider multipl...

This paper develops a framework for analyzing individuals’ choices in the presence of endogenous social networks and implements it with data on teen smoking decisions and friendship networks. By allowing actions and friendships to be jointly chosen, the framework extends the literature on social interactions, which either models choices, taking the social network as given, or which models frien...

Evidences suggest that in some villages of developing countries, agents rely on mutual insurance agreements to deal with income or expenditure shocks. In this paper we analyze which risk-sharing networks can be sustained in the long run when individuals are farsighted rather than myopic, in the sense that they are able to forecast how other agents would react to their actions. In particular, we...

We study a model where agents, located in a social network, decide whether to exert e¤ort or not in experimenting with a new technology (or acquiring a new skill, innovating, etc.). We assume that agents have strong incentives to free ride on their neighbors’e¤ort decisions. In the static version of the model e¤orts are chosen simultaneously. In equilibrium, agents exerting e¤ort are never conn...

We study a dynamic learning model in which heterogeneously connected Bayesian players choose between two activities: learning from one’s own experience (work) or learning from the experience of others (search). Players who work produce an inflow of information which is local and dispersed across the society. Players who search aggregate the information produced by others and facilitate its diff...

H/ACA RNA-guided ribonucleoprotein particle (RNP), the most complicated RNA pseudouridylase so far known, uses H/ACA guide RNA for substrate capture and four proteins (Cbf5, Nop10, L7Ae and Gar1) for pseudouridylation. Although it was shown that Gar1 not only facilitates the product release, but also enhances the catalytic activity, the chemical role that Gar1 plays in this complicated machiner...

The acquisition and dispersion of information, a critical aspect of economic decisions, can occur through a network of agents (Jackson, 2009). Empirical and theoretical findings suggest that an efficient information dispersion network takes the form of a star: small numbers of agents gather information and distribute it to a large group. Controlled tests of this theory, however, have typically ...