Informations and abstract
In order to understand the evolution of the systems of firms it is important to single out the factors, causing aggregation and decomposition processes among units operating within a production cycle. The following analysis aims at defining these factors by studying information processing mechanisms moving from an atypical view: the production process as an abstract sequence of discrete units. Necessary principles to organize a sequence architecture are thus defined, above all according to the ways of determining the basic parameters in the development of production phases; indeed, two models of adaptation processes among the production phases are described: selective systems and top-down systems. The concept of evolutionary hierarchies, basic to both models, allows to define two mechanisms (specific variants, rearrangement of routines), acting within the evolutionary processes of sets of units. Finally, the analysis of the relationships between evolutionary mechanims and environmental characteristics allow to show factors (coordination requirements and coordination costs), which are essential to explain evolutionary patterns of systems of firms.