2021/12/27 by Petruševski, Mirko, Škrekovski, Riste · 4 citations
#05C15 #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.2112.13710
In this short paper, we introduce a new vertex coloring whose motivation comes from our series on odd edge-colorings of graphs. A proper vertex coloring φ of graph G is said to be odd if for each non-isolated vertex x∈ V(G) there exists a color c such that φ-1(c)∩ N(x) is odd-sized. We prove that every simple planar graph admits an odd 9-coloring, and conjecture that 5 colors always suffice.