?有向曲线弧

... 第二类曲线积分 line integrals of the second type 有向曲线弧 directed arc 单连通区域 simple connected region ...

?有向连接弧

(2)P是库所(place)的非空有限集; (3)T是变迁(transition)的非空有限集; (4)A是有向连接弧(directed arc)的有限集,且有POT=ellA=TNA=a; (5)C:(P set);