Robust Coordination in Networks

We study the robustness of binary-action heterogeneous network coordination games equipped with an external field modeling the different players' biases towards one action with respect to the other one. We prove necessary and sufficient conditions for global stability of consensus equilibria under best response type dynamics, robustly with respect to (constant or time-varying) values of the external field. We then apply these results to the analysis of mixed network coordination and anti-coordination games and find sufficient conditions for existence and global stability of pure strategy Nash equilibria. Our results apply to general weighted directed interaction networks and build on supermodularity properties of the coordination games in order to characterize conditions for the existence of a novel notion of robust improvement and best response paths.