Long-Run Scale Adjustments of a Perfectly Competitive Firm and Industry: An Alternative Approach
利用成本函数技术，以简洁有力的方式推导了Ferguson和Saving关于完全竞争企业与行业长期规模调整的结果，展示了该技术相较于传统比较静态方法的优势。
The purpose of this note is to use the cost function technique to derive the results of the recent article in this Review by C. E. Ferguson and Thomas Saving (hereafter F-S). Our interest lies not so much in the results as in the simplicity and power of the technique itself, in contrast to the rather cumbersome conventional apparatus of comparative statics micro-theory.1 We shall not, therefore, discuss in detail the F-S interpretations of their results, although the technique should give the reader a more intuitive grasp of what is going on. Following F-S, we assume that the production function f(x) is increasing in each input, strictly concave and twice continuously differentiable on the positive orthant. All equilibrium input vectors are assumed strictly positive. We start from the duality between production and cost functions demonstrated by Shephard, Uzawa, and McFadden; under our assumptions, the production function may be uniquely characterized by its minimum total cost function, defined for all p>0 by2 () C=min ptixi f(x) = q}