摘要
简单图G的粘合运算G_(uv)指的是重合G的两个顶点{u,v}并且去掉重边和环所得到简单图的运算.本文考虑了粘合运算对图的4个控制参数γ(G),Γ(G),β(G),i(G)的影响.刻画了图G_(uv)与图G的控制参数γ(G),Γ(G),γ(G),i(G)之间的关系.及给出γ(G_(uv))=γ(G)-1和β(G_(uv)=β(G)-1的充要条件.
Let G be a simple graph and u, v∈V(G). The graph Guv, is called the vertex-contraction of G, if we identify the vertices u and v and remove all resulting loops and duplicate edges. This paper deals with the relationship of domination parameters between Guv. and G, and gets γ(Guv)=γ(G) or γ(Guv) = γ(G) - 1,Γ(Guv) = Γ(G) or Γ(Guv) =Γ(G) - 1, β(Guv) = β(G) or β(Guv) =β(G) - 1. The sufficient and necessary conditions for γ(Guv) = γ(G) - 1 and β(Guv) =β(G) - 1 are also obtained.
基金
国家自然科学基金(10171022)
关键词
粘合运算
控制数
上控制数
独立控制数
独立数
vertex-contraction
domination number
upper domination number
independent domination number
independence number.