A medianoid problem is a competitive location problem that determines the locations of a number of new service facilities that are competing with existing facilities for service to customers. This paper studies the medianoid problem on the plane with Manhattan distance. For the medianoid problem...

Competing firms may engage in group buying to benefit from quantity discount from the common supplier. There are two prevailing power structures in industry practice: Nash group buying in which two competing firms possess similar powers, and Stackelberg group buying in which one firm serves as...