ArticleOriginal scientific text
Title
2-distance 4-colorability of planar subcubic graphs with girth at least 22
Authors 1, 2
Affiliations
- Institute of Mathematics, Siberian Branch of the Russian Academy of Sciences, and Novosibirsk State University, Novosibirsk, 630090, Russia
- Institute of Mathematics at Yakutsk State University and North-Eastern Federal University, Yakutsk, 677891, Russia
Abstract
The trivial lower bound for the 2-distance chromatic number χ₂(G) of any graph G with maximum degree Δ is Δ+1. It is known that χ₂ = Δ+1 if the girth g of G is at least 7 and Δ is large enough. There are graphs with arbitrarily large Δ and g ≤ 6 having χ₂(G) ≥ Δ+2. We prove the 2-distance 4-colorability of planar subcubic graphs with g ≥ 22.
Keywords
planar graph, subcubic graph, 2-distance coloring
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