Relations between economic variables are often characterized by a situation where initial conditions and the past realizations of economic variables matter. I.e. past (transient) exogenous disturbances and past states of the economic system do have an influence on the current economic relations....

A non-linear model is applied where suddenly strong spurts of exports occur when changes of the exchange rate go beyond a zone of inaction. We call the latter a 'play' area – analogous to mechanical play and implement an algorithm describing path dependent play-hysteresis into a regression...