Okun’s law and anelastic relaxation in economics

We unify the gap, difference and dynamic versions of Okun’s law using the theory of anelasticity. This theory provides a straightforward and parsimonious approach to macroeconomic model construction that we illustrate by treating the time-dependence of Okun’s law generated by labor migration. We also show how this approach provides a natural way of expressing the phenomena of macroeconomic friction due to the kinetic adjustment of microeconomic variables.