【摘要】 设Sn是具有n个顶点至多有2个等长圈的简单图的集合。若Sn中不存在图G’使|E（C’）|>|E（G）|,Ng称G是简单的最大图分布（2）图（简记为简单MCD（2）图）。用f^*（n,2）表示具有n个顶点的简单MCD（2）图的边数。作者证明了f^*（n,2）≥（n-l）+[1/2（11n-20）^1/2]且当3≤n≤10时等式成立。更多还原

【Abstract】 Let Sn be the set of simple graphs on n vertices in which at most two cycles have the same length. A graph C is said to be a simple maximum cycle distributed(2) graph (Simple MCD(2)-graph) if there does not exist a graph G1 in Sn such that IE( G’) | > | E( G)| . Let f (n,2) be the number of edges in a simple MCD(2) - graph on n vertices. In this paper , we provethat f(n,2) > (n - 1) + [1/2,11n -20]for each integer n >3 , and the equality holds when更多还原