2023/07/31 by Aoki, Kengo · 4 citations
#05C15 #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2307.16394
A 2-distance k-coloring of a graph G is a proper k-coloring such that any two vertices at distance two or less get different colors. The 2-distance chromatic number of G is the minimum k such that G has a 2-distance k-coloring, denote as χ2(G). In this paper, we show that χ2(G) ≤ 17 for every planar graph G with maximum degree Δ≤ 5, which improves a former bound χ2(G) ≤ 18.