中国科学技术大学学报 ›› 2021, Vol. 51 ›› Issue (5): 374-381.DOI: 10.52396/JUST-2021-0119

• 研究论文:数学 • 上一篇    下一篇

染色数为5和6的图中的圈长

火清羿*   

  1. 中国科学技术大学数学科学学院,安徽合肥 230026
  • 收稿日期:2021-04-17 修回日期:2021-05-25 出版日期:2021-05-31 发布日期:2021-12-01
  • 通讯作者: * E-mail:qyhuo@mail.ustc.edu.cn

Cycle lengths in graphs of chromatic number five and six

Huo Qingyi*   

  1. School of Mathematical Sciences, University of Science and Technology of China, Hefei 230026, China
  • Received:2021-04-17 Revised:2021-05-25 Online:2021-05-31 Published:2021-12-01
  • Contact: * E-mail: qyhuo@mail.ustc.edu.cn

摘要: Moore和West提出问题:每一个(k+1)-临界的非完全图中是否存在一个模k的意义下长度为2的圈.这里证明了更强的结论:对于k=4, 5,每一个(k+1)-临界的非完全图中一定存在模k的意义下所有长度的圈.

关键词: 圈长, 染色数, 最小度, 广度优先搜索树

Abstract: A problem was proposed by Moore and West to determine whether every (k+1)-critical non-complete graph has a cycle of length 2 modulo k. We prove a stronger result that for k=4, 5, every (k+1)-critical non-complete graph contains cycles of all lengths modulo k.

Key words: cycle length, chromatic number, minimum degree, breadth-first search tree

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