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arXiv · 2312.14576

Packing coloring of hypercubes with extended Hamming codes

Petr Gregor·Jaka Kranjc·Borut Lužar·Kenny Štorgel
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Abstract

A {\em packing coloring} of a graph $G$ is a mapping assigning a positive integer (a color) to every vertex of $G$ such that every two vertices of color $k$ are at distance at least $k+1$. The least number of colors needed for a packing coloring of $G$ is called the {\em packing chromatic number} of $G$. In this paper, we continue the study of the packing chromatic number of hypercubes and we improve the upper bounds reported by Torres and Valencia-Pabon ({\em P. Torres, M. Valencia-Pabon, The packing chromatic number of hypercubes, Discrete Appl. Math. 190--191 (2015), 127--140}) by presenting recursive constructions of subsets of distant vertices making use of the properties of the extended Hamming codes. We also answer in negative a question on packing coloring of Cartesian products raised by Bre\v{s}ar, Klav\v{z}ar, and Rall ({\em Problem 5, Bre\v{s}ar et al., On the packing chromatic number of Cartesian products, hexagonal lattice, and trees. Discrete Appl. Math. 155 (2007), 2303--2311.}).

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Petr Gregor, Jaka Kranjc, Borut Lužar, Kenny Štorgel. 2023-12-22. Packing coloring of hypercubes with extended Hamming codes. https://doi.org/10.1016/j.dam.2024.07.048

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