Social Network Formation with Consent

We investigate the equilibria of game theoretic models of network formation that are based on individual actions only.Our approach is grounded in three simple and realistic principles: (1) Link formation should be a binary process of consent.(2) Link formation should be costly.(3) The class of network payoff functions should be as general as possible.It is accepted that these consent models have a very large number of equilibria.However, until now no characterization of these equilibria has been established in the literature.We aim to fill this void and provide characterizations of stable networks or the cases of two-sided and one-sided link formation costs.Furthermore, we provide a comparison of Nash equilibria with potential maximizers for a certain specification.game theory;general equilibrium

Stable Networks and Convex Payoffs

Recently a variety of link-based stability concepts have emerged in the literature on game theoretic models of social network formation.We investigate two basic formation properties that establish equivalence between some well known types of stable networks and their natural extensions.These properties can be identified as convexity conditions on the network payoff structures.social networks;network formation;pairwise stability

The Role of Trust in Costly Network Formation

We consider game theoretic models of social network formation.In this paper we limit our investigation to game theoretic models of network formation that are based on individual actions only.Our approach is based on three simple and realistic principles: (1) Link formation is a binary process of consent.(2) Link formation is costly.(3) The class of network payo functions should be as general as possible.We provide characterizations of stable networks under the hypothesis of mutual consent in the cases of two-sided and one-sided link formation costs. Furthermore, we introduce a new equilibrium concept based on a limited, realistic form of farsightedness or "trust" in network formation.game theory;models;general equilibrium;stability

Charge order suppression and antiferromagnetic to ferromagnetic switch over in Pr_0.5Ca_0.5MnO_3 nanowires

We have prepared crystalline nanowires (diameter ~ 50 nm, length ~ a few microns) of the charge ordering manganite Pr_0.5Ca_0.5Mn_O3 using a low reaction temperature hydrothermal method and characterized them using X-ray diffraction, transmission electron microscopy, SQUID magnetometry and electron magnetic resonance measurements. While the bulk sample shows a charge ordering transition at 245 K and an antiferromagnetic transition at 175 K, SQUID magnetometry and electron magnetic resonance experiments reveal that in the nanowires phase, a ferromagnetic transition occurs at ~ 105 K. Further, the antiferromagnetic transition disappears and the charge ordering transition is suppressed. This result is particularly significant since the charge order in Pr_0.5Ca_0.5MnO_3 is known to be very robust, magnetic fields as high as 27 T being needed to melt it.Comment: 12 pages including 4 figures. submitted to Applied Physics Letter