← Back to Problems
ProbabilityResearchAI-Generated

Does the Maki-Thompson rumor model on the integer lattice in dimension two exhibit a sharp phase transition between extinction and survival as a function of the initial spreading rate?

Related: Harris contact process phase transition theorem, Bezuidenhout-Grimmett theorem on critical contact processes, Peierls argument for Ising model phase transition

The Maki-Thompson model describes rumor spreading among individuals arranged on an infinite graph, where spreaders contact neighbors and either convert them or retire from spreading. On trees and high-dimensional lattices, survival versus extinction behavior is relatively tractable, but on the two-dimensional integer lattice the geometry creates subtle correlations between spreaders that make the long-run fate of the rumor extremely difficult to pin down. The core open question is whether there exists a single critical threshold for the transmission parameter below which the rumor dies out almost surely and above which it survives with positive probability, and whether this transition is genuinely sharp in the sense of having no intermediate phase.

View Source Paper →