%0 Journal Article %T 平面图的平方染色数的一个新上界<br>New upper bound on the chromatic number of the square of a planar graph %A 朱海洋 %A 顾 毓 %A 吕新忠< %A br> %A ZHU Hai-yang %A GU Yu %A Lü Xin-zhong %J 山东大学学报(理学版) %D 2016 %R 10.6040/j.issn.1671-9352.0.2014.594 %X 摘要: 令V(G)、E(G)、Δ(G)和χ(G)分别为G的顶点集、边集、最大度和色数。图G的平方图,记为G2,指的是一个图满足条件:V(G2)=V(G),并且uv∈E(G2)当且仅当1≤dG(u,v)≤2。证明了若G是Δ(G)≤6且围长g(G)≥5的平面图,则χ(G2)≤Δ(G)+8。<br>Abstract: Let V(G), E(G), Δ(G) and χ(G) denote the vertex set, the edge set, the maximum degree and the chromatic number of a graph G, respectively. The square G2 of a graph G is defined such that V(G2)=V(G), and uv∈E(G2)if and only if 1≤dG(u,v)≤2. It is proved that χ(G2)≤Δ(G)+8 if G is a planar graph with Δ(G)≤6 and girth g(G)≥5 %K 平面图 %K 染色 %K 围长 %K 平方图 %K < %K br> %K planar graph %K girth %K coloring %K squares %U http://lxbwk.njournal.sdu.edu.cn/CN/10.6040/j.issn.1671-9352.0.2014.594