Title: The Strategic Formation of Multi-Layer Networks
Many real-world networks consist of multiple layers of relationships between a common set of nodes. Examples include friendship and professional relationships in social networks, different transportation networks between a set of cities, and coupled communication and energy infrastructure networks. In this talk, we describe a model to capture the strategic formation of multi-layer networks, where each layer is designed to maximize some utility that depends on the topology of that layer and those of the other layers. We start by generalizing distance-based network formation to the two-layer setting, where edges are constructed in one layer (with fixed cost per edge) to minimize distances between nodes that are neighbors in another layer. We show that designing an optimal network in this setting is NP-hard. Despite the underlying complexity of the problem, we characterize certain properties of the optimal networks. We then formulate a multi-layer network formation game where each layer corresponds to a player that is optimally choosing its edge set in response to the edge sets of the other players. For utility functions that view the different layers as strategic substitutes, we show that players with low edge-costs drive players with high edge-costs out of the game, and that hub-and-spoke networks that are commonly observed in transportation systems arise as Nash equilibria in this game.
Shreyas Sundaram is an Assistant Professor in the School of Electrical and Computer Engineering at Purdue University. He received his Ph.D. in Electrical Engineering from the University of Illinois at Urbana-Champaign in 2009, and was a Postdoctoral Researcher at the University of Pennsylvania from 2009 to 2010. He was an Assistant Professor at the University of Waterloo from 2010 to 2014. At Waterloo, he received the Department of Electrical and Computer Engineering Research Award in 2014, the University of Waterloo Outstanding Performance Award in 2013 and the Faculty of Engineering Distinguished Performance Award in 2012. He received the M. E. Van Valkenburg Graduate Research Award and the Robert T. Chien Memorial Award from the University of Illinois, both for excellence in graduate research, and he was a finalist for the Best Student Paper Award at the 2007 and 2008 American Control Conferences. His research interests include network science, large-scale dynamical systems, fault-tolerant and secure control, linear system and estimation theory, and the application of algebraic graph theory to system analysis.