“…Remark 2.1. The above four assumptions are conventional for consensus control of multiple Euler-Lagrange systems with disturbances or actuator faults (see [14,18,22,28,9,2,19,4,33,3,21,32]). In fact, Assumption 2.1 implies that the leader is a root node of the graph G, and hence H is invertible (see [7]), which is necessary for control design.…”