A note on integer programming methods for mixed radial Moore graphs

Abstract

Mixed radial Moore graphs are approximations of mixed Moore graphs that preserve the distance-preserving spanning tree for some vertices. One way to measure their resemblance to a mixed Moore graph is using the status measure. The status of a graph is defined as the sum of the distances between all pairs of ordered vertices. Mixed radial Moore graphs with minimum status are closer to mixed Moore graphs according to this measure. The existence of mixed radial Moore graphs is still unknown for most values of the degree and the diameter. In this work, we develop an integer programming model (IP) to find mixed radial Moore graphs of diameter 3 with minimum status. As a result, we show the existence of these graphs for several new values of the degree and the diameter.