Opinion dynamics on a co-evolving topology
Adaptive networks allow topology and state to co-evolve. In the adaptive voter model (Vazquez et al. 2008), each agent holds opinion +/− (red/blue). At each step, a discordant edge is chosen: with probability φ it is rewired (connecting same-opinion nodes), with probability 1−φ the minority node copies the majority. This competition between rewiring (segregation) and copying (consensus) produces a fragmentation transition at φ_c: below it, consensus emerges; above it, the network breaks into opinion fragments.