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
The Weights of the Edges in Arrangements of Open Semicircles
摘要/Abstract
摘要：
在S1上n个开半圆的简单配置中,顶点或边的权是指包含它的半圆个数,vk,ek分别表示权为k的顶点数和边数,向量v=(v0,v1,…,vn-1)称为配置的v向量 ,e=(e0 ,e1,…,en)称为配置的e-向量。讨论了非负整数(n+1)数组(e0 ,e1,…,en)是S1上n个半圆的配置的边的频率向量的充分必要条件。
Abstract：
In an arrangement of n open semicircles on S1,the weight of a vertex or an edge is defined to be the number of semicircles containing it.The number of vertices or edges having weight k is denoted by vk or ek,respectively.v=(v0,v1,…,vn-1)is called the v-vector,and e=(e0,e1,…,en)the e-vector of the arrangement.A necessary and sufficient condition is discussed for an (n+1)-tuple(e0,e1,…,en) of no n-negative integers to be the frequency vector of the edges of an arrangement of n semicircles on S1.
关键词
Key words：
arrangement
;
weight of edge
;
frequency vector of edges