期刊信息
- 刊名： 河北师范大学学报（自然科学版）Journal of Hebei Normal University (Natural Science)
- 主办： 河北师范大学
- ISSN： 1000-5854
- CN： 13-1061/N
- 中国科技核心期刊
- 中国期刊方阵入选期刊
- 中国高校优秀科技期刊
- 华北优秀期刊
- 河北省优秀科技期刊
A Necessary and Sufficient Condition About the Connectivity of the R-rotation Graph of a Coronoid System
摘要/Abstract
六角系统的R-旋转图是1棵有向根树,但冠状系统的R-旋转图是一个有向森林,其底图不一定连通.如果冠状系统是基本的,已经证明其R-旋转图至少包含2棵有向根树.利用有向根树间的一种乘法运算,证明了一个冠状系统的R-旋转图为1棵有向根树当且仅当该冠状系统的每个基本分支都是六角系统.
The R-rotation graph of a hexagonal system is a directed rooted tree.But for a coronoid system,its R-rotation graph is a multiple directed rooted tree,of which each component is a directed rooted tree.It is proved that the R-rotation graph of a elementary coronoid system is a multiple directed rooted tree containing at least 2 trees.Using a multiplication operation between multiple directed rooted trees,it is proved that the R-rotation graph of a coronoid system Hc is a directed rooted tree if and only if each elementary component of Hc is a hexagonal system.