Activities (or production processes) are considered as building blocks out of which a technology is constructed. Postulates are developed by which activities may be combined. The main part of the paper is concerned with the discrete type model and the use of a linear maximization function for finding the "optimum" program. The mathematical problem associated with this approach is developed first in general notation and then in term sof a dynamic system of equations expressed in matrix notation. Typical problems from the fields of inter-industryrelations, transportation nutrition, warehouse storage, and air transport are given in the last section.