New upper bounds on the L(2, 1)-labeling of the skew and converse skew product graphs
New upper bounds on the L(2, 1)-labeling of the skew and converse skew product graphs
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偏斜和逆偏斜积图的 L(2, 1) 标记的新上限
DOI:
10.1016/j.tcs.2011.01.031
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发表时间:
2011
期刊:
影响因子:
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通讯作者:
Cuiqi Wang
中科院分区:
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作者:
Ziming Duan;Pingli Lv;L. Miao;Z. Miao;Cuiqi Wang
An L(2,1)-labeling of a graph G is defined as a function f from the vertex set V(G) into the nonnegative integers such that for any two vertices x, y, |f(x)−f(y)|≥2 if d(x,y)=1 and |f(x)−f(y)|≥1 if d(x,y)=2, where d(x,y) is the distance between x and y in G. The L(2,1)-labeling number λ2,1(G) of G is the smallest number k such that G has an L(2,1)-labeling with k=max{f(x)|x∈V(G)}. In this paper, we consider the graph formed by the skew product and converse skew product of two graphs, and give new upper bounds of the L(2,1)-labeling number, which improves the upper bounds obtained by Shao and Zhang [Z.D. Shao, D. Zhang, Improved upper bounds on the L(2,1)-labeling of the skew and converse skew product graphs, Theoret. Comput. Sci. 400 (2008) 230–233] in many cases.
DOI:
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