数学物理学报

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ON THE CROSSING NUMBER OF THE COMPLETE TRIPARTITE GRAPH K1,8,n

黄元秋; 赵霆雷   

  1. 湖南师范大学数学系, 长沙 410081
  • 收稿日期:2005-06-28 修回日期:1900-01-01 出版日期:2006-12-25 发布日期:2006-12-25
  • 通讯作者: 黄元秋
  • 基金资助:
    This work is supported by the Key Project of the Education Department of Hunan Province of China (05A037) and by Scientific Research Fund of Hunan Provincial Education Department (06C515).

ON THE CROSSING NUMBER OF THE COMPLETE TRIPARTITE GRAPH K1,8,n

Huang Yuanqiu; Zhao Tinglei   

  1. Department of Mathematics, Hunan Normal University, Changsha 410081, China
  • Received:2005-06-28 Revised:1900-01-01 Online:2006-12-25 Published:2006-12-25
  • Contact: Huang Yuanqiu

摘要: The well known Zarankiewicz' conjecture is said that the crossing number of the complete bipartite graph Km,n (m≤ n) is Z(m,n), where Z(m,n)=\lfloor\frac{m}{2}\rfloor\lfloor\frac{m-1}{2}\rfloor\lfloor\frac{n}{2}\rfloor$$\lfloor\frac{n-1}{2}\rfloor$ (for any real number x, $\lfloor x\rfloor$ denotes the maximal integer no more than x). Presently, Zarankiewicz' conjecture is proved true only for the case m≤ 6. In this article, the authors prove that if Zarankiewicz' conjecture holds for m≤9, then the crossing number of the complete tripartite graph K1,8,n is $Z(9, n)+ 12\lfloor\frac{n}{2}\rfloor$.

关键词: Graphs, Drawing, Crossing number, Complete tripartite graph, Complete tripartite graph

Abstract: The well known Zarankiewicz' conjecture is said that the crossing number of the complete bipartite graph Km,n (m≤ n) is Z(m,n), where Z(m,n)=\lfloor\frac{m}{2}\rfloor\lfloor\frac{m-1}{2}\rfloor\lfloor\frac{n}{2}\rfloor$$\lfloor\frac{n-1}{2}\rfloor$ (for any real number x, $\lfloor x\rfloor$ denotes the maximal integer no more than x). Presently, Zarankiewicz' conjecture is proved true only for the case m≤ 6. In this article, the authors prove that if Zarankiewicz' conjecture holds for m≤ 9, then the crossing number of the complete tripartite graph K1,8,n is $Z(9, n)+ 12\lfloor\frac{n}{2}\rfloor$.

Key words: Graphs, Drawing, Crossing number, Complete tripartite graph, Complete tripartite graph

中图分类号: 

  • 05C10