分别连结六阶图G1的6个顶点与其它n个顶点,得到一类特殊的图Hn,运用组合方法、归纳思想及反证法证明了Hn的交叉数为X(6,n)+2|n/2|,并在此基础上证明G1与星K1,n的笛卡尔积的交叉数为Z(6,n)+2|n/2|;另外,证明了含子图S5的其它6个六阶图与星K1,n的笛卡尔积的交叉数都为Z(6,n)+4|n/2|.
A special family of graph denotcd by Hn is obtained by combination the 6- vertices of G1 to other n vertices. The combinaton method anti the induction thought as the reducton were utilized. It is proved that the crossing number of H,, is Z(6,n) + n, 2|n/2|, and the crossing number of Cartesian products of G1 and star K1,n is Z(6, n) + 2|n/2|. The (:tossing number of Cartesian products of Gj(j = 2,3,……,7) whit'h contains the subgraph S5 and star K1,n is Z(6, n)+4|n/2|.