Probabilistic Diffusion in Random Network Graphs

TL;DR

This study investigates how information spreads in random networks with probabilistic links and diffusion, revealing that the success rate of diffusion remains constant regardless of the number of initial adopters, while the speed increases.

Contribution

It reports a novel invariant property of successful diffusion fraction in random networks, independent of the number of early adopters, which was not previously documented.

Findings

Success rate of diffusion is invariant to the number of early adopters.

Average rounds per successful diffusion decrease with more early adopters.

The invariant property is observed for fixed link and diffusion probabilities.

Abstract

In this paper, we consider a random network such that there could be a link between any two nodes in the network with a certain probability (plink). Diffusion is the phenomenon of spreading information throughout the network, starting from one or more initial set of nodes (called the early adopters). Information spreads along the links with a certain probability (pdiff). Diffusion happens in rounds with the first round involving the early adopters. The nodes that receive the information for the first time are said to be covered and become candidates for diffusion in the subsequent round. Diffusion continues until all the nodes in the network have received the information (successful diffusion) or there are no more candidate nodes to spread the information but one or more nodes are yet to receive the information (diffusion failure). On the basis of exhaustive simulations conducted in this paper, we observe that for a given plink and pdiff values, the fraction of successful diffusion attempts does not appreciably change with increase in the number of early adopters; whereas, the average number of rounds per successful diffusion attempt decreases with increase in the number of early adopters. The invariant nature of the fraction of successful diffusion attempts with increase in the number of early adopters for a random network (for fixed plink and pdiff values) is an interesting and noteworthy observation (for further research) and it has not been hitherto reported in the literature.