Título: Fast Consensus and Metastability in a Highly Polarized Social Network
Palestrante: Antonio Galves (IME-USP and NeuroMat)
Local: Transmissão online
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Resumo: Discrepancy between the results of electoral intentions carried out a few days before the actual voting and the electoral poll results during the first round of the 2018 presidential elections in Brazil was striking. At the time, it was conjectured that this discrepancy was the result of social-media campaigning days before the elections. The question remains: is social-media campaigning enough to change the voting intention of a significant portion of voters? To provide an answer to this question was the initial motivation for this work. The model we consider is a system with a large number of interacting marked point processes with memory of variable length. Each point process indicates the successive times in which a social actor expresses a "favorable'' (+1) or "contrary'' (-1) opinion on a certain subject. The social pressure on an actor determines the orientation and the rate at which he expresses opinions. When an actor expresses their opinion, social pressure on them is reset to 0, and simultaneously social pressure on the other actors is changed by one unit in the direction of the opinion that was just expressed. The network has a polarization coefficient that indicates the tendency of social actors to express an opinion in the same direction of the social pressure exerted on them. We show that when the polarization coefficient diverges consensus is reached almost instantaneously. Moreover, in a highly polarized network, consensus has a metastable behavior and changes its direction after a long and unpredictable random time. This is a joint work and a joint talk with Kádmo de Souza Laxa.
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