Uniform edge betweenness centrality

Heather Newman (Department of Mathematics Princeton University USA)
Hector Miranda (School of Mathematical Sciences Rochester Institute of Technology USA)
Rigoberto Flórez (Department of Mathematics and Computer Science, The Citadel USA)
Darren A Narayan (School of Mathematical Sciences Rochester Institute of Technology USA)

Electronic Journal of Graph Theory and Applications (EJGTA)
Vol 8, No 2 (2020): Electronic Journal of Graph Theory and Applications

The edge betweenness centrality of an edge is loosely defined as the fraction of shortest paths between all pairs of vertices passing through that edge. In this paper, we investigate graphs where the edge betweenness centrality of edges is uniform. It is clear that if a graph G is edge-transitive (its automorphism group acts transitively on its edges) then G has uniform edge betweenness centrality. However this sufficient condition is not necessary. Graphs that are not edge-transitive but have uniform edge betweenness centrality appear to be very rare. Of the over 11.9 million connected graphs on up to ten vertices, there are only four graphs that are not edge-transitive but have uniform edge betweenness centrality. Despite this rarity among small graphs, we present methods for creating infinite classes of graphs with this unusual combination of properties.