一个双色有向图D是本原的,如果存在非负整数h和k,h+k〉0,使得D的每对顶点(i,j),都存在从i到j的(h,k)-途径,并称h+k的最小值为双色有向图D的本原指数.文章给出了一类双色有向图的本原指数集,并对其极图进行刻画.
A two-colored digraph D is primitive if there exist nonnegative integers h and k with h+k〉0 such that for each pair(i,j) of vertices there existts an(h,k)-walk in D from i to j. The exponent of the primitive two-colored digraph D is the minimum value of hq-k taken over all such h and k. We give the exponent set of a class of primitive two-colored digraphs, and the characterizations of the extremal two-colored digraphs.