Krein parameters and antipodal tight graphs with diameter 3 and 4

被引：30
|
作者：
Jurisic, A
Koolen, J
机构：
[1] IMFM, Nova Gorica, Slovenia
[2] Nova Gorica Polytech, Nova Gorica, Slovenia
[3] Univ Bielefeld, FSP, D-33501 Bielefeld, Germany
来源：
DISCRETE MATHEMATICS | 2002年 / 244卷 / 1-3期
关键词：
Krein parameters; distance-regular graphs; tight graphs; 1-homogeneous graphs; antipodal graphs; locally strongly-regular; Taylor graphs;
D O I：
10.1016/S0012-365X(01)00082-6
中图分类号：
O1 [数学];
学科分类号：
0701 ; 070101 ;
摘要：
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(11)(4) vanishes. (C) 2002 Elsevier Science B.V. All rights reserved.
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页码：181 / 202
页数：22
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