强竞赛图中的外弧4泛顶点

4-Pancyclic Vertices of Out-Arcs in Strong Tournaments

在强连通竞赛图中外弧泛圈顶点的基础上,研究了强连通竞赛图中外弧4泛顶点的数目.利用路收缩的方法,证明了下面结论:设T是一个s-强(s≥3)竞赛图,M是T中具有最小出度的顶点的集合,如果|M|≥3,则T至少包含s+2个外弧4泛顶点.

On the basis of out-arc pancyelic vertices in strong tournaments, the number of out-arc 4- pancyclic vertices in s-strong （s≥3） tournament were investigated. The following result is proved by using path-contracting method. Let T be a s-strong （s≥3） tournament, and let M be a set of some vertices with minimum out-degree. If I M≥ 3, then T contains at least s ＋ 2 out-arc 4-pancyclic vertices.