Abstract
A k-edge coloring \(\varphi \) of a graph G is injective if \(\varphi (e_1)\ne \varphi (e_3)\) for any three consecutive edges \(e_1, e_2\) and \(e_3\) of a path or a triangle. The injective chromatic index \(\chi _i'(G)\) of G is the smallest k such that G admits an injective k-edge coloring. By discharging method, we demonstrate that any graph with maximum degree \(\Delta \le 5\) has \(\chi _i'(G)\le 12\) (resp. 13) if its maximum average degree is less than \(\frac{20}{7}\) (resp. 3), which improves the results of Zhu (2023).




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Acknowledgements
This work is supported by National Natural Science Foundation of China (No. 12371338), Anhui Provincial Natural Science Foundation (No. 2108085MA01), Outstanding Youth Scientific Research Projects of Anhui Provincial Department of Education (No. 2022AH030073) and Key Projects in Natural Science Research of Anhui Provincial Department of Education (No. 2023AH050268, 2022AH050594).
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National Natural Science Foundation of China (No. 12371338).
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Lu, J., Hong, ZM. & Xia, ZJ. On injective chromatic index of sparse graphs with maximum degree 5. J Comb Optim 48, 41 (2024). https://doi.org/10.1007/s10878-024-01234-7
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DOI: https://doi.org/10.1007/s10878-024-01234-7