Formulation of normal form equations of nonlinear networks containing memristors and coupled elements

This paper presents a variety of sufficient conditions for the existence of a set of normal form equations of a connected nonseparable network, which may contain coupled elements. An network is defined as a network containing independent (but not necessarily time-independent) current and voltage sources, nonlinear time-invariant resistors, inductors, capacitors, and memristors. Via an example, this paper shows that the class of networks under consideration, in fact, includes networks containing multiterminal network elements and controlled sources.