by exploiting the disequilibrium and non linear relationships among economic aggregates. Prom an empirical point of view, this approach resemblaces the old NBER view, according to which: "the business cycle . . . ] consists of - pansions occurring at about the same time in many economic activities, f- lowed by similairly general recessions, contractions, and revivals which merge into the expansion phase of the next cyxle" (Burns and Mitchell, 1946). They add that the movement, although recurrent, is not periodic, lasting from 1 to 12 years, and it is not divisible into shorter cycles. Of...