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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Main Authors: Fan Yang, Xiangwen Li, Ziwen Huang
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Mathematics
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Online Access:https://www.mdpi.com/2227-7390/13/2/190
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author Fan Yang
Xiangwen Li
Ziwen Huang
author_facet Fan Yang
Xiangwen Li
Ziwen Huang
author_sort Fan Yang
collection DOAJ
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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institution Kabale University
issn 2227-7390
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publishDate 2025-01-01
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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