# Graph fission in an evolving voter model.

Published

Journal Article

We consider a simplified model of a social network in which individuals have one of two opinions (called 0 and 1) and their opinions and the network connections coevolve. Edges are picked at random. If the two connected individuals hold different opinions then, with probability 1 - α, one imitates the opinion of the other; otherwise (i.e., with probability α), the link between them is broken and one of them makes a new connection to an individual chosen at random (i) from those with the same opinion or (ii) from the network as a whole. The evolution of the system stops when there are no longer any discordant edges connecting individuals with different opinions. Letting ρ be the fraction of voters holding the minority opinion after the evolution stops, we are interested in how ρ depends on α and the initial fraction u of voters with opinion 1. In case (i), there is a critical value α(c) which does not depend on u, with ρ ≈ u for α > α(c) and ρ ≈ 0 for α < α(c). In case (ii), the transition point α(c)(u) depends on the initial density u. For α > α(c)(u), ρ ≈ u, but for α < α(c)(u), we have ρ(α,u) = ρ(α,1/2). Using simulations and approximate calculations, we explain why these two nearly identical models have such dramatically different phase transitions.

### Full Text

### Duke Authors

### Cited Authors

- Durrett, R; Gleeson, JP; Lloyd, AL; Mucha, PJ; Shi, F; Sivakoff, D; Socolar, JES; Varghese, C

### Published Date

- March 2012

### Published In

### Volume / Issue

- 109 / 10

### Start / End Page

- 3682 - 3687

### PubMed ID

- 22355142

### Pubmed Central ID

- 22355142

### Electronic International Standard Serial Number (EISSN)

- 1091-6490

### International Standard Serial Number (ISSN)

- 0027-8424

### Digital Object Identifier (DOI)

- 10.1073/pnas.1200709109

### Language

- eng