Columbia University Joint CS/EE Networking Seminar Series

Diffusion and Cascading Behavior in Random Networks

Dr. Marc Lelarge

INRIA and Ecole Normale Supérieure

Thursday, June 2nd at 11am EE Conference Room (13th floor MUDD)

Abstract: The spread of new ideas, behaviors or technologies has been extensively studied using epidemic models. Here we consider a model of diffusion where the individuals' behavior is the result of a strategic choice. We study a simple coordination game with binary choice and give a condition for a new action to become widespread in a random network. We also analyze the possible equilibria of this game and identify conditions for the coexistence of both strategies in large connected sets. Finally we look at how can firms use social networks to promote their goals with limited information. Our results differ strongly from the one derived with epidemic models and show that connectivity plays an ambiguous role: while it allows the diffusion to spread, when the network is highly connected, the diffusion is also limited by high-degree nodes which are very stable.

Speaker Biography: Marc Lelarge graduated from Ecole Polytechnique (Palaiseau, France) in 1999 and qualified as an engineer at Ecole Nationale Supérieure des Télécommunications (Paris, France) in 2001. He received his PhD degree in Applied Mathematics from Ecole Polytechnique in 2005 and is research scientist at INRIA since 2006. His main research interests are in random graphs, combinatorial optimization and economics of networks.