3-hued coloring of planar graphs
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摘要: 对于整数k,r>0,图G的(k,r)-染色是一个正常k染色,使得对于每一个度数为d(v)的点v,v的邻点至少表现min{d(v),r}种颜色, 这样的染色,称之为r-hued染色, 图G的r-hued染色数, 记作$\chi_{r}(G)$,是使图G存在(k,r)染色的最小的k值. 在这篇文章中, 证明了,对于一般平面图G, $\chi_{3}(G)\leq 12$.Abstract: For a fixed integer k,r>0, a (k,r)-coloring of a graph G is a proper k-coloring such that for any vertex v with degree d(v), the adjacent vertex of v is adjacent to at least $\min\{d(v),r\}$ different colors. Such coloring is also called as a r-hued coloring. The r-hued chromatic number of G, denoted by $\chi_{r}(G)$, is the smallest integer k such that G has a (k, r)-coloring. In this paper, we prove that if G is a planar graph, then $\chi_{3}(G) \leq 12$.
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Key words:
- planar graphs /
- minimal counterexample /
- Lebesgue formula
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