一个绘制统筹图的算法

统筹图又叫计划网络图。任给一个其元素叫做工序（或作业或活动）的有限偏序集，要绘制它的一个最优统筹图，限含虚工序数目为最少者，是一个尚未从理论上解决的问题。本文讨论了虚工序产生的原因和如何减少虚工序数量的一些途径；指出了高度为二的编序集其最优统筹图含虚工序数目达到最大且等于该偏序集框图的边数的充分必要条件；本文给出了一个绘制最优统筹图的近似算法，此算法弥补了文2]和3]所给算法的一些不足之处。

An Algorithm for Constructing PERT Networks

Let P be a partially ordered set (poset) the elements of which are known as tasks or activities. It is still an unsolved problem to construct an optimum PERT network (having the smallist number of dummy tasks)of P. In this paper,a new appproximate algorithm for constructing an optimal PERT network of a poset is given. It is also givin. It is also given a characterixation of a poset,with the hight two, the optimum PERT network of which has the largest number of dummy tasks which is equal to the number of edges of the diagram of the poset.