An Upper Bound for the Crossing Number of Locally Twisted Cubes

Haoli Wang1, Xirong Xu2, Yuansheng Yang2, Bao Liu2, Wenping Zheng3, Guoging Wang4
1College of Computer and Information Engineering Tianjin Normal University, Tianjin, 300387, P. R. China
2Department of Computer Science Dalian University of Technology, Dalian, 116024, P. R. China
3Key Laboratory of Computational Intelligence and Chinese Information Processing of Ministry of Education, Shanxi University, Taiyuan, 030006, P. R. China
4Department of Mathematics Tianjin Polytechnic University, Tianjin, 300387, P. R. China

Abstract

The crossing number of a graph \(G\) is the minimum number of pairwise intersections of edges in a drawing of \(G\). The \(n\)-dimensional locally twisted cubes \(LTQ_n\), proposed by X.F. Yang, D.J. Evans and G.M. Megson, is an important interconnection network with good topological properties and applications. In this paper, we mainly obtain an upper bound on the crossing number of \(LTQ_n\), no more than \(\frac{265}{6}4^{n-4} – (n^2 + \frac{15+(-1)^{n-1}}{6}2^{n-3}\).