Technical Note - On Location Dominance on Spherical Surfaces

In a recent paper Aly et al. (Aly, A. A., D. C. Kay, D. W. Litwhiler, Jr. 1979. Location dominance on spherical surfaces. Opns. Res. 27 972–981.) proved that an optimal solution to a “minisum” problem on a sphere must lie in the convex hull of the demand points if the demand points are not located entirely on a great circle arc. The case when all demand points are on a great circle arc remains an open question. In this note we prove that if demand points are located on a great circle arc, so is the optimal solution point.