Cyclic-order graphs and Zarankiewicz's crossing-number conjecture
✍ Scribed by D. R. Woodall
- Publisher
- John Wiley and Sons
- Year
- 1993
- Tongue
- English
- Weight
- 750 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Zarankiewicz's conjecture, that the crossing number of the complete‐bipartite graph K~m, n~ is [1/2 m] [1/2 (m] −1) [1/2 n] [1/2 (n −1)], was proved by Kleitman when min(m, n) ≤ 6, but was unsettled in all other cases. The cyclic‐order graph CO__n__ arises naturally in the study of this conjecture; it is a vertex‐transitive harmonic diametrical (even) graph. In this paper the properties of cyclic‐order graphs are investigated and used as the basis for computer programs that have verified Zarankiewicz's conjecture for K~7,7~ and K~7,9~; thus the smallest unsettled cases are now K~7,11~ and K~9,9~. © 1993 John Wiley & Sons, Inc.
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