Abstract
A graph is H-free if it does not contain an induced subgraph isomorphic to H. We denote by P k the path on k vertices. In this paper, we prove that 4-COLORING is NP-complete for P 7-free graphs, and that 5-COLORING is NP-complete for P 6-free graphs. The second result is the first NP-completeness shown for any k-COLORING of P 6-free graphs. These two results improve two previously best results and almost complete the classification of complexity of k-COLORING P t -free graphs for k ≥ 4 and t ≥ 1, leaving as the only missing case 4-COLORING P 6-free graphs. Our NP-completeness results use a general framework, which we show is not sufficient to prove the NP-completeness of 4-COLORING P 6-free graphs. We expect that 4-COLORING is polynomial solvable for P 6-free graphs.
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Huang, S. (2013). Improved Complexity Results on k-Coloring P t -Free Graphs. In: Chatterjee, K., Sgall, J. (eds) Mathematical Foundations of Computer Science 2013. MFCS 2013. Lecture Notes in Computer Science, vol 8087. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-40313-2_49
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DOI: https://doi.org/10.1007/978-3-642-40313-2_49
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