Rumor processes in random environment on N and on Galton-Watson trees

TL;DR

This paper investigates rumor spreading processes in random environments on linear and Galton-Watson trees, providing conditions for their survival or extinction based on the structure and station distribution.

Contribution

It introduces new models of rumor processes in random environments on trees and characterizes their survival conditions, extending previous work to more complex stochastic structures.

Findings

Survival conditions are established for rumor processes on 1D trees with random stations.

Survival on Galton-Watson trees is characterized, with positive probability implying almost sure survival.

Sufficient conditions for extinction and survival are provided in various cases.

Abstract

The aim of this paper is to study rumor processes in random environment. In a rumor process a signal starts from the stations of a fixed vertex (the root) and travels on a graph from vertex to vertex. We consider two rumor processes. In the firework process each station, when reached by the signal, transmits it up to a random distance. In the reverse firework process, on the other hand, stations do not send any signal but they "listen" for it up to a random distance. The first random environment that we consider is the deterministic 1-dimensional tree N with a random number of stations on each vertex; in this case the root is the origin of N. We give conditions for the survival/extinction on almost every realization of the sequence of stations. Later on, we study the processes on Galton-Watson trees with random number of stations on each vertex. We show that if the probability of survival is positive, then there is survival on almost every realization of the infinite tree such that there is at least one station at the root. We characterize the survival of the process in some cases and we give sufficient conditions for survival/extinction.