Termination time of multidimensional Hegselmann-Krause opinion dynamics

We consider the Hegselmann-Krause model for opinion dynamics in higher dimensions. Our goal is to investigate the termination time of these dynamics, which has been investigated for a scalar case, but remained an open question for dimensions higher than one. We provide a polynomial upper bound for the termination time of the dynamics when the connectivity among the agents maintains a certain structure. Our approach is based on the use of an adjoint dynamics for the Hegselmann-Krause model and a Lyapunov comparison function that is defined in terms of the adjoint dynamics.