摘要
给出了有界开集的边界的一个拓扑性质：如果Ｄ是平面Ｒ２中原点的有界开邻域，那么其边界Ｄ中有一个连通分支与平面中从原点出发的任意射线都相交．
The following theorem is proved:Theorem. Let D be a bounded open neighbourhood of the origin of R2,then the boundary D has a connected component which intersects every ray starting from the origin.
出处
《山东大学学报（理学版）》
CAS
CSCD
1994年第3期299-304,共6页
Journal of Shandong University(Natural Science)
关键词
有界开集
边界
拓扑性质
bounded open set
boundary
topological property
