The discussion centers on the challenges of formulating Ohm's law for nonlinear metamaterials, particularly in relation to the equations presented in a research paper. The user is trying to derive the microscopic form of Ohm's law, expressing current density (j) in terms of electric field (E) and impedance (Imp). They explore the relationships between resistance (R), reactance (X), and the variables involved, ultimately seeking clarity on the correct formulation. The conversation highlights the need to reconcile different expressions of impedance and resistivity in the context of nonlinear properties. Understanding these relationships is crucial for accurately applying Ohm's law to nonlinear metamaterials.