谈包络曲线在实践运用中的矛盾

On the Application Contradiction of Containing Net Curve

包络曲线是西方经济学中的基本概念之一,是长期成本分析工具之一。在有的经济学教材中,关于包络曲线的论述存在前后不一致的矛盾。笔者认为,在生产规模可无限细分的条件下,包络曲线是由无数条短期成本曲线最低点轨迹构成的长期成本曲线;对于长期平均成本曲线,它是短期平均成本曲线的包络曲线,它是一条“U”型曲线,无论是在“U”型曲线的下降阶段还是上升阶段,它都与短期平均成本曲线的最低点相切。

Containing Net Curve is one of the basic concepts in the Western Economics, and one of the tools of analyzing the Long Cost. In some related economics textbooks, some illustrations about Containing Net Curve are inconsistent. In this paper, the writer thinks that in the condition of indefinite segmentation in producing scale, Containing Net Curve is the Long Cost Curve, which is constituted by the lowest orbit of numerous Short Cost Curves. As for the Long Average Cost （LAC）, it is the Containing Net Curve of the Short Average Cost Curve with ＂U＂ form. And no matter in the descending stage or in the rising stage, it is tangent with the lowest point of the Short Average Cost Curve.