The capital-theoretic model suggested for determining the price- quantity combinations does not hold in the case of most natural resources, including petroleum, since the inelastic demand function would vitiate the optimal solution. The specification of a dynamic demand function, with necessary, attributes, no doubt, results in a valid optimal solution in period t, but that could be achieved only at the cost of sub-optimal solution in other periods. If the OPEC starts behaving as a discriminating monopoly, instead of as a pure monopoly, the optimal solution is assured in all markets and in all time periods
