2024/12/24 by Chen, Kaizhe, Liu, Shiping
#Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2412.18480
In this paper, we derive new sharp diameter bounds for distance regular graphs, which better answer a problem raised by Neumaier and Penji' c in many cases. Our proof is built upon a relation between the diameter and long-scale Ollivier Ricci curvature of a graph, which can be considered as an improvement of the discrete Bonnet-Myers theorem. Our method further leads to significant improvements of existing diameter bounds for amply regular graphs and (s,c,a,k)-graphs.