On the state equations of nonlinear networks and the uniqueness of their solutions

Concerning the equilibrium points and the uniqueness of solutions, some wrong results have appeared recently about the state description of nonlinear networks; in contrast to those results in [1], it is shown through the same example that every critical (or singular) point where the state derivative vanishes is not an equilibrium point, and the state description in terms of the capacitor voltage leads to a unique solution consistent with the physical constraints of the network.