Abstract
A locally identifying coloring (lid-coloring) of a graph is a proper vertex-coloring such that the sets of colors appearing in the closed neighborhoods of any pair of adjacent vertices having distinct neighborhoods are distinct. Our goal is to study a relaxed locally identifying coloring (rlid-coloring) of a graph that is similar to locally identifying coloring for which the coloring is not necessarily proper. We denote by \(\chi _{rlid}(G)\) the minimum number of colors used in a relaxed locally identifying coloring of a graph G. In this paper, we prove that the problem of deciding that \(\chi _{rlid}(G)=3\) for a 2-degenerate planar graph G is NP-complete and for a bipartite graph G is polynomial. We give several bounds of \(\chi _{rlid}(G)\) for different families of graphs and construct new graphs for which these bounds are tight. We also compare this parameter with the minimum number of colors used in a locally identifying coloring of a graph G (\(\chi _{lid}(G)\)), the size of a minimum identifying code of G (\(\gamma _{id}(G)\)) and the chromatic number of G (\(\chi (G)\)).
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Our acknowledgements go to the referees for careful reading and helpful remarks to improve this paper.
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Aïder, M., Gravier, S. & Slimani, S. Relaxed Locally Identifying Coloring of Graphs. Graphs and Combinatorics 32, 1651–1665 (2016). https://doi.org/10.1007/s00373-016-1677-z
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DOI: https://doi.org/10.1007/s00373-016-1677-z