"The paper presents a linear programming model of production activities of the US economy after nuclear attack. The model has many alternative combinations of agricultural production for meeting specific nutritive element requirements of the population and one production process for each nonagricultural output. The processes for nonagricultural output are those of the 1958 Interindustry Model of the US Office of Business Economics; the agricultural activities draw on many other sources of data. Rows of the model generally state that the cumulative product of variables and their coefficients must be less than or equal to either zero or some stipulated capacity. In the former case the typical row states that inputs required minus production of the item must not be greater than zero. In the latter case the requirements refer to capacities, which cannot be produced in a static model, and total requirements must not exceed the stipulated capacity remaining after the nuclear attack."
United Stated Federal Emergency Management Agency, Learning Resource Center: http://www.lrc.fema.gov/