Width and dual width of subsets in polynomial association schemes
SCIE
SCOPUS
- Title
- Width and dual width of subsets in polynomial association schemes
- Authors
- Brouwer, AE; Godsil, CD; Koolen, JH; Martin, WJ
- Date Issued
- 2003-05
- Publisher
- ACADEMIC PRESS INC ELSEVIER SCIENCE
- Abstract
- The width of a subset C of the vertices of a distance-regular graph is the maximum distance which occurs between elements of C. Dually, the dual width of a subset in a cometric association scheme is the index of the "last" eigenspace in the Q-polynomial ordering to which the characteristic vector of C is not orthogonal. Elementary bounds are derived on these two new parameters. We show that any subset of minimal width is a completely regular code and that any subset of minimal dual width induces a cometric association scheme in the original. A variety of examples and applications are considered. (C) 2003 Elsevier Science (USA). All rights reserved.
- Keywords
- association scheme; distance-regular graph; near polygon; DESIGNS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/29783
- DOI
- 10.1016/S0097-3165(0
- ISSN
- 0097-3165
- Article Type
- Article
- Citation
- JOURNAL OF COMBINATORIAL THEORY SERIES A, vol. 102, no. 2, page. 255 - 271, 2003-05
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