罗美金, 高玉斌. Primitive Exponents of a Class of Two-Colored Digraphs[J]. 2008, (2): 95-100.DOI:
一类双色有向图的本原指数
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+k0
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.考虑了一类特殊的双色有向图
它的未着色图含有m+1个顶点
且包含一个m-圈和一个n-圈.给出了某种本原条件和指数上界
并对达到指数最大界的极图进行了刻划.
Abstract
A two-colored directed graph D is primitive if there exist nonnegative integers h and k with h+k0 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 class of special two-colored digraphs whose uncolored digraph has m+1 vertices and consists of one m-cycle and one n-cycle are considered.Some primitive conditions and an upper bound on the exponents are presented.The extremal two-colored digraphs are characterized.
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references
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