竞赛图的本原指数及其极图刻划

Primitive Exponents of Tournament and the Characterizations of Their Extreme Digraphs

设Ｄ 为ｎ 阶强连通竞赛图．证明了当ｎ ≥５ 时，Ｄ 的本原指数３ ≤ｒ（Ｄ） ≤ｎ ＋ ２，并给出了达到最大值ｎ ＋ ２ 的极图的完全刻划及达到最小值３

Let D be the diconnected tournament on n vertices,proved that 3≤r(D)≤n+2 and provided a complete characterization of the extreme digraph as r(D) obtains its maximum n+2 ,and some of the sufficient conditions as r(D) obtains its minimum 3.