开半圆的配置中边的权  

The Weights of the Edges in Arrangements of Open Semicircles

作　　者：李英姿[1] 李建国[2] 

机构地区：[1]河北师范大学数学与信息科学学院,河北石家庄050016 [2]石家庄农业学校基础部,河北石家庄050041

出　　处：《河北师范大学学报（自然科学版）》2002年第4期345-348,共4页Journal of Hebei Normal University：Natural Science

基　　金：河北省自然科学基金资助项目 (199174)

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 .In an arrangement of n open semicircles on S 1,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 v k or e k ,respectively.v=( v 0, v 1,..., v n-1 ) is called the v vector,and e=( e 0, e 1,..., e n ) the e vector of the arrangement.A necessary and sufficient condition is discussed for an (n+1) tuple (e 0,e 1,...,e n) of non negative integers to be the frequency vector of the edges of an arrangement of n semicircles on S 1.

关 键 词：开半圆 配置 边 权 频率向量 V-向量 e-向量 顶点 充要条件 

分 类 号：O157.3[理学—数学]