Structure économique et périodes longues

[eng] SUMMARY The economic thought after the overwhelming Keynesian infatuation turns again to the long run problems In this regard new central notion has been brought out the economic structure What does this term mean For the needs of empirical research we tbial that definition of the structure can only be given by referring to the long run It appears then as combination of lasting relations or more precisely of relations which most often vary slowly Most often means that sudden changes may occur in the different elements of the structure These can be divided into four sections population productive resources natural data and accumulated capital) technique and institution? The structure changes divide long periods in the historical and not in the Marshallian sense These long periods are those during which structure is steady enough One can regard them as almost homoge neous as said Aherman Then the characteristics of these long periods are underlined They may be used as hypothesis in the researches on the long run evolution