Equitable colorings of Cartesian products of graphs
Equitable colorings of Cartesian products of graphs
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DOI:
10.1016/j.dam.2011.09.020
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发表时间:
2012-02
期刊:
影响因子:
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通讯作者:
Wu-Hsiung Lin;G. Chang
中科院分区:
文献类型:
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作者:
Wu-Hsiung Lin;G. Chang
The present paper studies the following variation of vertex coloring on graphs. A graph G is equitably k-colorable if there is a mapping f:V(G)→{1,2,…,k} such that f(x)≠f(y) for xy∈E(G) and ∣∣f−1(i)∣−∣f−1(j)∣∣≤1 for 1≤i,j≤k. The equitable chromatic number of a graph G, denoted by χ=(G), is the minimum k such that G is equitably k-colorable. The equitable chromatic threshold of a graph G, denoted by χ=∗(G), is the minimum t such that G is equitably k-colorable for all k≥t. Our focus is on the equitable colorability of Cartesian products of graphs. In particular, we give exact values or upper bounds of χ=(G□H) and χ=∗(G□H) when G and H are cycles, paths, stars, or complete bipartite graphs.