Latency-bounded target set selection in signed networks

It is well-documented that social networks play a considerable role in information spreading. The dynamic processes governing the diffusion of information have been studied in many fields, including epidemiology, sociology, economics, and computer science. A widely studied problem in the area of viral marketing is the target set selection: in order to market a new product, hoping it will be adopted by a large fraction of individuals in the network, which set of individuals should we “target” (for instance, by offering them free samples of the product)? In this paper, we introduce a diffusion model in which some of the neighbors of a node have a negative influence on that node, namely, they induce the node to reject the feature that is supposed to be spread. We study the target set selection problem within this model, first proving a strong inapproximability result holding also when the diffusion process is required to reach all the nodes in a couple of rounds. Then, we consider a set of restrictions under which the problem is approximable to some extent

Local majorities, coalitions and monopolies in graphs: a review

AbstractThis paper provides an overview of recent developments concerning the process of local majority voting in graphs, and its basic properties, from graph theoretic and algorithmic standpoints

Irreversible Dynamos in Tori

We study the dynamics of majority-based distributed systems in presence of permanent faults. In particular, we are interested in the patterns of initial faults which may lead the entire system to a faulty behaviour. Such patterns are called dynamos and their properties have been studied in many different contexts. In this paper we investigate dynamos for meshes with different types of toroidal closures. For each topology we establish tight bounds on the number of faulty elements needed for a system break-down, under different majority rules. Keywords: Distributed Computing, Tori, Majority Rule, Fault Tolerance. 1 Introduction Consider the following repetitive process on a synchronous network G: initially each vertex is in one of two states (colors), black or white; at each step, all vertices simultaneously (re)color themselves either black or white, each according to the color of the "majority" of its neighbors (majority rule). Different processes occur depending on how majority is d..