Some Comments on the Stevens Linear and Quadratic Programming Versions of von Thünen's Theory of Agricultural Land Usage

This paper examines the Stevens linear and quadratic programming formulations of von Thünen's analysis of agricultural land usage (Stevens, 1968). The first section contains a description of the Walras—Wald version of general economic equilibrium, plus a working definition of the expressions: general equilibrium sketch, paticularised general equilibrium sketch, and partial equilibrium sketch. [The author's distinction between a sketch and a model is explained in Macmillan (1978).] In section 2, von Thünen's assumptions, Stevens's (first) revised version of those assumptions, and Stevens's linear programming model are described. In section 3, the relationship between the Stevens linear programming model and the Walras—Wald model is examined. The fourth section contains a description of Stevens's approach to the relaxation of von Thünen's assumption of infinite demand elasticity, and a comparison of that approach with the so-called partial equilibrium approach to the same problem. It is claimed that this comparison is of some general, methodological interest. Section 5 contains the paper's conclusions.