Power in the Heterogeneous Connections Model: The Emergence of Core-Periphery Networks

The heterogeneous connections model is a generalization of the homogeneous connections model of Jackson and Wolinsky (1996) in which the intrinsic value of each connection is set by a discrete, positive and symmetric function that depends solely on the types of the two end agents. Core periphery networks are defined as networks in which the agents' set can be partitioned into two subsets, one in which the members are completely connected among themselves and the other where there are no internal links. A two-type society is defined as "power based" if both types of agents prefer to connect to one of the types over the other, controlling for path length. An exhaustive analysis shows that core periphery networks, in which the "preferred" types are in the core and the "rejected" types are in the periphery, are crucial in the "power based" society. In particular, if the linking costs are not too low and not too high, at least one such network is pairwise stable. Moreover, in many cases these networks are the unique pairwise stable networks and in all cases they are the unique strongly efficient networks. The set of efficient networks often differs from the set of pairwise stable networks, hence a discussion on this issue is developed. These results suggest heterogeneity accompanied by "power based" linking preferences as a natural explanation for many core-periphery structures observed in real life social networks.Network Formation, Heterogeneity, Pairwise Stability

Negotiation across multiple issues

In the present work, agreement on allocation of payments from multiple issues requires unanimous consent of all parties involved. The agents are assumed to know the aggregate payoffs but do not know their decomposition by issues. This framework applies to many real-world problems, such as the formation of joint ventures. We present a novel solution concept to the problem, termed the multi-core, wherein an agent consents to participate in the grand coalition if she can envision a decomposition of the proposed allocation for which each coalition to which she belongs derives greater benefit on each issue by cooperating with the grand coalition rather than operating alone. An allocation is in the multi-core if all agents consent to participate in the grand coalition. We provide a theorem characterizing the non-emptiness of the multi-core and show that the multi-core generalizes the core. We prove that the approach of the multi-core has the potential to increase cooperation among parties beyond that of solving issues independently. In addition, we establish that the multi-core wherein agents take into account the specifics of the original issues is a refinement of the core of the sum of individual issues in which such information is ignored

Power in the Heterogeneous Connections Model: The Emergence of Core-Periphery Networks

The heterogeneous connections model is a generalization of the homogeneous connections model of Jackson and Wolinsky (1996) in which the intrinsic value of each connection is set by a discrete, positive and symmetric function that depends solely on the types of the two end agents. Core periphery networks are defined as networks in which the agents' set can be partitioned into two subsets, one in which the members are completely connected among themselves and the other where there are no internal links. A two-type society is defined as "power based" if both types of agents prefer to connect to one of the types over the other, controlling for path length. An exhaustive analysis shows that core periphery networks, in which the "preferred" types are in the core and the "rejected" types are in the periphery, are crucial in the "power based" society. In particular, if the linking costs are not too low and not too high, at least one such network is pairwise stable. Moreover, in many cases these networks are the unique pairwise stable networks and in all cases they are the unique strongly efficient networks. The set of efficient networks often differs from the set of pairwise stable networks, hence a discussion on this issue is developed. These results suggest heterogeneity accompanied by "power based" linking preferences as a natural explanation for many core-periphery structures observed in real life social networks

Power in the heterogeneous connections model: The emergence of core-periphery networks

The heterogeneous connections model is a generalization of the homogeneous connections model of Jackson and Wolinsky (1996) in which the intrinsic value of each connection is set by a discrete, positive and symmetric function that depends solely on the types of the two end agents. Core periphery networks are defined as networks in which the agents' set can be partitioned into two subsets, one in which the members are completely connected among themselves and the other where there are no internal links. A two-type society is defined as power based if both types of agents prefer to connect to one of the types over the other, controlling for path length. An exhaustive analysis shows that core periphery networks, in which the preferred types are in the core and the rejected types are in the periphery, are crucial in the power based society. In particular, if the linking costs are not too low and not too high, at least one such network is pairwise stable. Moreover, in many cases these networks are the unique pairwise stable networks and in all cases they are the unique strongly efficient networks. The set of efficient networks often differs from the set of pairwise stable networks, hence a discussion on this issue is developed. These results suggest heterogeneity accompanied by power based linking preferences as a natural explanation for many core-periphery structures observed in real life social networks

Social Clubs and Social Networks

We present a strategic network formation model based on membership in clubs. Individuals choose affiliations. The set of all memberships induces a weighted network where two individuals are directly connected if they share a club. Two individuals may also be indirectly connected using multiple memberships of third parties. Individuals gain from their position in the induced network and pay membership fees. We study the club congestion model where the weight of a link decreases with the size of the smallest shared club. A trade-off emerges between the size of clubs, the depreciation of indirect connections, and the membership fee. (JEL D71, D85, Z13) </jats:p