Digraphs have a simple pictorial representation.

有向图有简单的图形表示。

Digraphs should not be typed with adjacent fingers.

高频组合不宜在相邻手指。

Some theorems about fundamental properties of the digraphs are proved.

本文证明了几个关于有向图基本性质的定理。

The hierarchical strategy for digraphs reduces search space for failure sources;

采用有向图分层策略，减小故障源搜索空间的大小；

Special primitive two-colored digraphs whose uncolored digraph consist of two cycles are considered.

研究一类特殊的本原双色有向图，其未着色的有向图包含两个圈。