两个双向圈的双色有向图的本原指数  

Exponents of Two-Colored Directed Graphs with Two Double-Directed Cycles

作　　者：周会玲[1] 邵燕灵[1] 

机构地区：[1]中北大学理学院,山西太原030051

出　　处：《中北大学学报（自然科学版）》2007年第6期471-474,共4页Journal of North University of China(Natural Science Edition)

基　　金：国家自然科学基金资助项目(10571163);山西省自然科学基金资助项目(20041010;2007011017)

摘　　要：一个双色有向图D是本原的,如果存在非负整数h和k,且h+k>0,使得D中的每一对顶点(i,j)都存在从i到j的(h,k)-途径,则称h+k的最小值为D的本原指数.本文考虑了一类特殊的双色有向图,它的未着色图有(2n-1)个顶点,包含4个n-圈和2n个2-圈,给出了本原条件和指数上界,没有给出一个紧上界.A two-colored directed graph D is primitive if there exist nonnegative integers h and k with h ＋k〉0 such that for each pair vertices （i,j） there exists an （h,k）-walk in D from i to j. The exponent of the primitive two-colored directed graph D is the minimum value of h＋k taken over all such h and k. A kind of special two-colored directed graph is considered, uncolored graph of which has 2n-1 vertices and consists of four n-cycle and 2n 2-cycle. Some primitive conditions and an upper exponent bound are presented, but the tight upper bound is not given.

关 键 词：双色有向图 指数 途径 

分 类 号：O157.5[理学—数学]