The crossing number of \((K_4-e)\times C_3\) (Q2715485)

The crossing number of a graph \(G\) is the minimum number of pairs of nonadjacent edges that intersect in any drawing of \(G\) in the plane. \textit{L. W. Beineke} and \textit{R. D. Ringeisen} [J. Graph Theory 4, 145-155 (1980; Zbl 0403.05037)] showed that the crossing number of the Cartesian product of the graph \(K_4 - e\) and the cycle of length \(n\) equals \(2n\) for \(n\geq 4\). The author of this note completes their result and proves that equality holds even in case \(n=3\).NEWLINENEWLINEFor the entire collection see [Zbl 0958.00021].