Sherwood C. Frey

Fractional Programming with Homogeneous Functions

This paper extends the well known results for linear fractional programming to the class of programming problems involving the ratio of nonlinear functionals subject to nonlinear constraints, where the constraints are homogeneous of degree one and the functionals are homogeneous of degree one to within a constant. Two rather general auxiliary problems are developed, and the relations between the solutions of the auxiliary problems and the solutions of the original problem are codified. Applications of the results for specific problems are also presented.

Equivalent Mathematical Programming Models of Pure Capital Rationing

In the applications of mathematical programming to the “pure capital rationing” problem, much of the attention has been focused on the search for an appropriate discount rate to account for the time value of money. The essential difficulty was first observed by Hirshleifer [10] in the classical economics context: “The discount rate to be used for calculating present values…cannot be discovered until the solution is attained, and so is of no assistance in reaching the solution.” Baumol and Quandt [1] showed that this problem persists in the Lorie and Savage [11] and Weingartner [15, Chap. 3] mathematical programming formulation and concluded that: “If there is capital rationing and external rates of interest are irrelevant, we cannot simultaneously insist on a present value formulation of the objective function and have the relevant discount rates determined internally by our program.” They then went on to propose an alternative utility formulation of the objective function.

Buckeye Power & Light Company

This case describes the coal-procurement process of a small electric utility. The manager of the production-fuel department must decide how much coal to purchase from each vendor and how to allocate the purchased coal among the utilitys three coal-burning plants. The situation can be modeled and solved as a linear program. Sensitivity analysis can be used to help formulate a strategy for negotiating with the vendors and to address other special issues.