The conventional description of a production possibility set or production function is obscure and unsatisfactory, if it is applied to dynamics. Its original function is for static analysis. It cannot precisely describe series of events which happen during the process of production. Production of any commodity may be stopped at any stage of execution. Such a truncated production resulting in intermediate products and more or less worn-out machines and equipment may itself form a complete activity for which an independent firm may be established which aims to produce intermediate products as its final products and sells them to other firms as parts of their products. For example, in the case of motorcar producing companies, the ratio of parts produced by other companies is high (over 70% of the total production of motorcars) in Japan, while considerably lower (40–50%) in the USA. It is rather difficult, though not impossible, to deal with this problem within the conventional framework of production functions or possibility sets.

In relation to the production possibility set there are three time elements. They are the production time of the commodity, the construction time of a production possibility set and the lifetime of capital goods. First the production time consists of the time needed to fill up the pipeline and the time it takes to produce one unit of a commodity after the pipeline to produce that commodity has been entirely filled up.