DMGT

ISSN 1234-3099 (print version)

ISSN 2083-5892 (electronic version)

https://doi.org/10.7151/dmgt

Discussiones Mathematicae Graph Theory

Journal Impact Factor (JIF 2022): 0.7

5-year Journal Impact Factor (2022): 0.7

CiteScore (2022): 1.9

SNIP (2022): 0.902

Discussiones Mathematicae Graph Theory

Article in volume


Authors:

K. Štorgel

Kenny Štorgel

Faculty of Information Studies, Novo mesto, Slovenia
University of Primorska, FAMNIT, Koper, Slovenia

email: kennystorgel.research@gmail.com

Title:

Improved bounds for some facially constrained colorings

PDF

Source:

Discussiones Mathematicae Graph Theory 43(1) (2023) 151-158

Received: 2020-03-24 , Revised: 2020-07-30 , Accepted: 2020-07-30 , Available online: 2020-09-12 , https://doi.org/10.7151/dmgt.2357

Abstract:

A facial-parity edge-coloring of a $2$-edge-connected plane graph is a facially-proper edge-coloring in which every face is incident with zero or an odd number of edges of each color. A facial-parity vertex-coloring of a $2$-connected plane graph is a proper vertex-coloring in which every face is incident with zero or an odd number of vertices of each color. Czap and Jendroľ in [Facially-constrained colorings of plane graphs: A survey, Discrete Math. 340 (2017) 2691–2703], conjectured that $10$ colors suffice in both colorings. We present an infinite family of counterexamples to both conjectures. A facial $(P_{k}, P_{\ell})$-WORM coloring of a plane graph $G$ is a vertex-coloring such that $G$ contains neither rainbow facial $k$-path nor monochromatic facial $\ell$-path. Czap, Jendroľ and Valiska in [WORM colorings of planar graphs, Discuss. Math. Graph Theory 37 (2017) 353–368], proved that for any integer $n\ge 12$ there exists a connected plane graph on $n$ vertices, with maximum degree at least $6$, having no facial $(P_{3},P_{3})$-WORM coloring. They also asked whether there exists a graph with maximum degree $4$ having the same property. We prove that for any integer $n\ge 18$, there exists a connected plane graph, with maximum degree $4$, with no facial $(P_{3},P_{3})$-WORM coloring.

Keywords:

plane graph, facial coloring, facial-parity edge-coloring, facial-parity vertex-coloring, WORM coloring

References:

  1. Cs. Bujtás, E. Sampathkumar, Zs. Tuza, C. Dominic and L. Pushpalatha, Vertex coloring without large polychromatic stars, Discrete Math. 312 (2012) 2102–2108.
    https://doi.org/10.1016/j.disc.2011.04.013
  2. Cs. Bujtás, E. Sampathkumar, Zs. Tuza, M. Subramanya and C. Dominic, $3$-consecutive c-colorings of graphs, Discuss. Math. Graph Theory 30 (2010) 393–405.
    https://doi.org/10.7151/dmgt.1502
  3. Cs. Bujtás and Zs. Tuza, F-WORM colorings: Results for $2$-connected graphs, Discrete Appl. Math. 231 (2017) 131–138.
    https://doi.org/10.1016/j.dam.2017.05.008
  4. J. Czap, Parity vertex coloring of outerplane graphs, Discrete Math. 311 (2011) 2570–2573.
    https://doi.org/10.1016/j.disc.2011.06.009
  5. J. Czap, Facial parity edge coloring of outerplane graphs, Ars Math. Contemp. 5 (2012) 289–293.
    https://doi.org/10.26493/1855-3974.228.ee8
  6. J. Czap, I. Fabrici and S. Jendroľ, Colorings of plane graphs without long monochromatic facial paths, Discuss. Math. Graph Theory 41 (2021) 801–808.
    https://doi.org/10.7151/dmgt.2319
  7. J. Czap and S. Jendroľ, Facially-constrained colorings of plane graphs: A survey, Discrete Math. 340 (2017) 2691–2703.
    https://doi.org/10.1016/j.disc.2016.07.026
  8. J. Czap, S. Jendroľ and F. Kardoš, Facial parity edge colouring, Ars Math. Contemp. 4 (2011) 255–269.
    https://doi.org/10.26493/1855-3974.129.be3
  9. J. Czap, S. Jendroľ, F. Kardoš and R. Soták, Facial parity edge colouring of plane pseudographs, Discrete Math. 312 (2012) 2735–2740.
    https://doi.org/10.1016/j.disc.2012.03.036
  10. J. Czap, S. Jendroľ and J. Valiska, WORM colorings of planar graphs, Discuss. Math. Graph Theory 37 (2017) 353–368.
    https://doi.org/10.7151/dmgt.1921
  11. J. Czap, S. Jendroľ and M. Voigt, Parity vertex colouring of plane graphs, Discrete Math. 311 (2011) 512–520.
    https://doi.org/10.1016/j.disc.2010.12.008
  12. W. Goddard, K. Wash and H. Xu, WORM colorings forbidding cycles or cliques, Congr. Numer. 219 (2014) 161–173.
  13. W. Goddard, K. Wash and H. Xu, WORM colorings, Discuss. Math. Graph Theory 35 (2015) 571–584.
    https://doi.org/10.7151/dmgt.1814
  14. T. Kaiser, O. Rucký, M. Stehlík and R. Škrekovski, Strong parity vertex coloring of plane graphs, Discrete Math. Theor. Comput. Sci. 16 (2014) 143–158.
  15. B. Lužar and R. Škrekovski, Improved bound on facial parity edge coloring, Discrete Math. 313 (2013) 2218–2222.
    https://doi.org/10.1016/j.disc.2013.05.022
  16. Zs. Tuza, Graph colorings with local constraints–-A survey, Discuss. Math. Graph Theory 17 (1997) 161–228.
    https://doi.org/10.7151/dmgt.1049
  17. V. Voloshin, The mixed hypergraphs, Comput. Sci. J. Moldova 1 (1993) 45–52.
  18. W. Wang, S. Finbow and P. Wang, An improved bound on parity vertex colourings of outerplane graphs, Discrete Math. 312 (2012) 2782–2787.
    https://doi.org/10.1016/j.disc.2012.04.009

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