CONVERGENCE SPEED OF UNSTEADY DISTRIBUTED CONSENSUS: DECAY ESTIMATE ALONG THE SETTLING SPANNING-TREES

Results for estimating the convergence rate of nonstationary distributed consensus algorithms are provided, on the basis of qualitative ( mainly topological) as well as basic quantitative information (lower-bounds on the matrix entries). The results appear to be tight in a number of instances and are illustrated through simple as well as more sophisticated examples. The main idea is to follow propagation of information along certain spanning-trees which arise in the communication graph.