an:01743021
Zbl 1024.05086
Juri??i??, Aleksandar; Koolen, Jack
Krein parameters and antipodal tight graphs with diameter 3 and 4
EN
Discrete Math. 244, No. 1-3, 181-202 (2002).
00082438
2002
j
05E30
distance-regular graphs; Taylor graphs
Authors' abstract: We determine which Krein parameters of nonbipartite antipodal distance-regular graphs of diameter 3 and 4 can vanish, and give combinatorial interpretations of their vanishing. We also study tight distance-regular graphs of diameter 3 and 4. In the case of diameter 3, tight graphs are precisely the Taylor graphs. In the case of antipodal distance-regular graphs of diameter 4, tight graphs are precisely the graphs for which the Krein parameter \(q^1_{11}\) vanishes.
R.E.L.Aldred (Dunedin)