By means of the analysis and summarization of dummy arrow s application in the activity-on-arrow network, a judgment criterion for dummy arrow s existence, direction and quantity is given.

• 通过对虚箭线在双代号网络图中的应用情况归纳及分析,给出了双代号网络图绘制中的虚箭线存在、指向及数目判定准则。