The simplest assumption that can be made is to assume that technical coefficients do not change as output levels change. Major output changes can be met by building new plants or by gradually dismantling existing ones. The remuneration of labour—which coincides with the value of the surplus—is proportional to the amounts of labour employed by each industry. No distinction on how this value will be distributed between classes is done at this stage of analysis. The proof of semi-positiveness of the solutions requires further analysis. Interest in the closed system is mainly due to its simplicity; moreover, besides representing the interdependencies between industries, it provides a first representation of the relations between each industry and the final sector. The determinants of the last column, that is, final consumptions, are quite uneven from those of the other columns, which are technical coefficients.