This paper analyses the definition of the DDGRAPH diagram and related concept,improves the method of designing the DDGRAPH diagram and the dominated tree,implied tree,unconstrained arc.

• 该文通过对DDGRAPH图的定义及相关概念的分析,对构建DDGRAPH图及支配树、蕴含树、非限制弧的方法进行了改进。