TY - JOUR T1 - Achieving unanimous opinions in signed social networks Y1 - 2014 A1 - Claudio Altafini A1 - Gabriele Lini AB - Being able to predict the outcome of an opinion forming process is an important problem in social network theory. However, even for linear dynamics, this becomes a difficult task as soon as non-cooperative interactions are taken into account. Such interactions are naturally modeled as negative weights on the adjacency matrix of the social network. In this paper we show how the Perron-Frobenius theorem can be used for this task also beyond its standard formulation for cooperative systems. In particular we show how it is possible to associate the achievement of unanimous opinions with the existence of invariant cones properly contained in the positive orthant. These cases correspond to signed adjacency matrices having the eventual positivity property, i.e., such that in sufficiently high powers all negative entries have disappeared. More generally, we show how for social networks the achievement of a, possibily non-unanimous, opinion can be associated to the existence of an invariant cone fully contained in one of the orthants of n. PB - Institute of Electrical and Electronics Engineers Inc. UR - http://urania.sissa.it/xmlui/handle/1963/34935 U1 - 35137 U2 - Mathematics U4 - 1 ER -