TY - JOUR
T1 - A note on triangle-free distance-regular graphs with a2 ≠ 0
AU - Pan, Yeh jong
AU - Weng, Chih-wen
PY - 2009/1
Y1 - 2009/1
N2 - Let Γ denote a distance-regular graph with classical parameters (D, b, α, β) and D ≥ 3. Assume the intersection numbers a1 = 0 and a2 ≠ 0. We show that the intersection number c2 is either 1 or 2, and if c2 = 1, then (b, α, β) = (- 2, - 2, ((- 2)D + 1 - 1) / 3).
AB - Let Γ denote a distance-regular graph with classical parameters (D, b, α, β) and D ≥ 3. Assume the intersection numbers a1 = 0 and a2 ≠ 0. We show that the intersection number c2 is either 1 or 2, and if c2 = 1, then (b, α, β) = (- 2, - 2, ((- 2)D + 1 - 1) / 3).
KW - Classical parameters
KW - Distance-regular graphs
UR - http://www.scopus.com/inward/record.url?scp=56449103622&partnerID=8YFLogxK
U2 - 10.1016/j.jctb.2008.07.005
DO - 10.1016/j.jctb.2008.07.005
M3 - Article
AN - SCOPUS:56449103622
SN - 0095-8956
VL - 99
SP - 266
EP - 270
JO - Journal of Combinatorial Theory. Series B
JF - Journal of Combinatorial Theory. Series B
IS - 1
ER -