Distance regular graphs of diameter 3 and strongly regular graphs
In a paper by \textit{N. L. Biggs} [Ann. Discrete Math. 15, 69-80 (1982; Zbl 0506.05057)], two parameter sets for distance regular graphs that are antipodal covers of a complete graph were mentioned for which the existence of a corresponding graph was unknown. In this paper both cases are settled by proving that one does not exist, while there are exactly two non-isomorphic solutions to the other. Also noted are some relations with strongly regular graphs and generalized quadrangles.
scientific article; zbMATH DE number 3855133