结点数为2^k—4的最小广播图

A Minimal Broadcasting Graph with 2~k-4 Nodes

改进了文献[7]给出的广播函数B（2k-4）（k≥4）的下界，构造了一个n＝2k－4的极小广播图，从而得到B（2k-4）（k≥4）的一个上界，并给出了一个mbg（28），该图的边数为48，达到B（28）的下界值．

In this paper, we improve the lower bound of the broadcasting function B(2k- 1) (k≥4)presented in the reference [7], construct a minimal broadcasting graph for n=2k-4, obtain an upper bound of B(2k-4), and give a mbg(28), whose edge number 48 reachis the lower bound of B(28).