DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles
In order to resolve Borodin’s Conjecture, DP-coloring was introduced in 2017 to extend the concept of list coloring. In previous works, it is proved that every planar graph without 7-cycles and butterflies is DP-4-colorable. And any planar graph that does not have 5-cycle adjacent to 6-cycle is DP-4...
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2025-01-01
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author | Fan Yang Xiangwen Li Ziwen Huang |
author_facet | Fan Yang Xiangwen Li Ziwen Huang |
author_sort | Fan Yang |
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description | In order to resolve Borodin’s Conjecture, DP-coloring was introduced in 2017 to extend the concept of list coloring. In previous works, it is proved that every planar graph without 7-cycles and butterflies is DP-4-colorable. And any planar graph that does not have 5-cycle adjacent to 6-cycle is DP-4-colorable. The existing research mainly focus on the forbidden adjacent cycles that guarantee the DP-4-colorability for planar graph. In this paper, we demonstrate that any planar graph <i>G</i> that excludes 7-cycles adjacent to <i>k</i>-cycles (for each <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>k</mi><mo>=</mo><mn>4</mn><mo>,</mo><mn>5</mn></mrow></semantics></math></inline-formula>), and does not feature a Near-bow-tie as an induced subgraph, is DP-4-colorable. This result extends the findings of the previous works mentioned above. |
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spelling | doaj-art-e9a7db265f5e4df29b82f25ee640905a2025-01-24T13:39:41ZengMDPI AGMathematics2227-73902025-01-0113219010.3390/math13020190DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-CyclesFan Yang0Xiangwen Li1Ziwen Huang2School of Mathematics and Science, Nanjing Tech University, Nanjing 211816, ChinaSchool of Mathematics & Statistics, Central China Normal University, Wuhan 430079, ChinaSchool of Mathematics and Computer Science & Center of Applied Mathematics, Yichun University, Yichun 336000, ChinaIn order to resolve Borodin’s Conjecture, DP-coloring was introduced in 2017 to extend the concept of list coloring. In previous works, it is proved that every planar graph without 7-cycles and butterflies is DP-4-colorable. And any planar graph that does not have 5-cycle adjacent to 6-cycle is DP-4-colorable. The existing research mainly focus on the forbidden adjacent cycles that guarantee the DP-4-colorability for planar graph. In this paper, we demonstrate that any planar graph <i>G</i> that excludes 7-cycles adjacent to <i>k</i>-cycles (for each <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>k</mi><mo>=</mo><mn>4</mn><mo>,</mo><mn>5</mn></mrow></semantics></math></inline-formula>), and does not feature a Near-bow-tie as an induced subgraph, is DP-4-colorable. This result extends the findings of the previous works mentioned above.https://www.mdpi.com/2227-7390/13/2/190planar graphDP-4-colorablelist coloring |
spellingShingle | Fan Yang Xiangwen Li Ziwen Huang DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles Mathematics planar graph DP-4-colorable list coloring |
title | DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles |
title_full | DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles |
title_fullStr | DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles |
title_full_unstemmed | DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles |
title_short | DP-4-Colorability on Planar Graphs Excluding 7-Cycles Adjacent to 4- or 5-Cycles |
title_sort | dp 4 colorability on planar graphs excluding 7 cycles adjacent to 4 or 5 cycles |
topic | planar graph DP-4-colorable list coloring |
url | https://www.mdpi.com/2227-7390/13/2/190 |
work_keys_str_mv | AT fanyang dp4colorabilityonplanargraphsexcluding7cyclesadjacentto4or5cycles AT xiangwenli dp4colorabilityonplanargraphsexcluding7cyclesadjacentto4or5cycles AT ziwenhuang dp4colorabilityonplanargraphsexcluding7cyclesadjacentto4or5cycles |