Specialized in Kron's formalism study from thirty years. I have extended Kron's formalism adding cords: generalized interactions including even game theory for human factor. I use this formalism in order to be able to write the equations of complex systems in electromagnetic compatibility. The objective is to study these systems theoretically. I'm convinced that numerical tools based on low order differential equations cannot be used without a preliminary theoretical work. This theoretical work is indispensable to demonstrate the adequacy of the numerical schematic used with the asymptotical behavior of these equations, when the discret intervals of space-time tends to zero. For example solving rigorously Maxwell's equations locally doesn't garantee obtaining the skin effect with its fractional derivative at a macroscopic scale.