Equitable Colorings Of Corona Multiproducts Of Graphs

A graph is equitably k-colorable if its vertices can be partitioned into k independent sets in such a way that the numbers of vertices in any two sets differ by at most one. The smallest k for which such a coloring exists is known as the equitable chromatic number of G and denoted by 𝜒=(G). It is kn...

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Main Authors: Furmánczyk Hanna, Kubale Marek, Mkrtchyan Vahan V.
Format: Article
Language:English
Published: Sciendo 2017-11-01
Series:Discussiones Mathematicae Graph Theory
Subjects:
Online Access:http://www.degruyter.com/view/j/dmgt.2017.37.issue-4/dmgt.1992/dmgt.1992.xml?format=INT
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spelling doaj-art-a6fe15ed05d445bca32d797b8b2b653c2018-09-02T19:13:13ZengSciendoDiscussiones Mathematicae Graph Theory2083-58922017-11-013741079109410.7151/dmgt.1992dmgt.1992Equitable Colorings Of Corona Multiproducts Of GraphsFurmánczyk Hanna0Kubale Marek1Mkrtchyan Vahan V.2Institute of Informatics, University of Gdánsk Wita Stwosza 57, 80-952 Gdánsk, PolandDepartment of Algorithms and System Modelling Gdánsk University of Technology Narutowicza 11/12, 80-233 Gdánsk, PolandDepartment of Informatics and Applied Mathematics Yerevan State University, Yerevan, ArmeniaA graph is equitably k-colorable if its vertices can be partitioned into k independent sets in such a way that the numbers of vertices in any two sets differ by at most one. The smallest k for which such a coloring exists is known as the equitable chromatic number of G and denoted by 𝜒=(G). It is known that the problem of computation of 𝜒=(G) is NP-hard in general and remains so for corona graphs. In this paper we consider the same model of coloring in the case of corona multiproducts of graphs. In particular, we obtain some results regarding the equitable chromatic number for the l-corona product G ◦l H, where G is an equitably 3- or 4-colorable graph and H is an r-partite graph, a cycle or a complete graph. Our proofs are mostly constructive in that they lead to polynomial algorithms for equitable coloring of such graph products provided that there is given an equitable coloring of G. Moreover, we confirm the Equitable Coloring Conjecture for corona products of such graphs. This paper extends the results from [H. Furmánczyk, K. Kaliraj, M. Kubale and V.J. Vivin, Equitable coloring of corona products of graphs, Adv. Appl. Discrete Math. 11 (2013) 103–120].http://www.degruyter.com/view/j/dmgt.2017.37.issue-4/dmgt.1992/dmgt.1992.xml?format=INTcorona graphequitable chromatic numberequitable coloring conjectureequitable graph coloringmultiproduct of graphsNP-completenesspolynomial algorithm.
institution Open Data Bank
collection Open Access Journals
building Directory of Open Access Journals
language English
format Article
author Furmánczyk Hanna
Kubale Marek
Mkrtchyan Vahan V.
spellingShingle Furmánczyk Hanna
Kubale Marek
Mkrtchyan Vahan V.
Equitable Colorings Of Corona Multiproducts Of Graphs
Discussiones Mathematicae Graph Theory
corona graph
equitable chromatic number
equitable coloring conjecture
equitable graph coloring
multiproduct of graphs
NP-completeness
polynomial algorithm.
author_facet Furmánczyk Hanna
Kubale Marek
Mkrtchyan Vahan V.
author_sort Furmánczyk Hanna
title Equitable Colorings Of Corona Multiproducts Of Graphs
title_short Equitable Colorings Of Corona Multiproducts Of Graphs
title_full Equitable Colorings Of Corona Multiproducts Of Graphs
title_fullStr Equitable Colorings Of Corona Multiproducts Of Graphs
title_full_unstemmed Equitable Colorings Of Corona Multiproducts Of Graphs
title_sort equitable colorings of corona multiproducts of graphs
publisher Sciendo
series Discussiones Mathematicae Graph Theory
issn 2083-5892
publishDate 2017-11-01
description A graph is equitably k-colorable if its vertices can be partitioned into k independent sets in such a way that the numbers of vertices in any two sets differ by at most one. The smallest k for which such a coloring exists is known as the equitable chromatic number of G and denoted by 𝜒=(G). It is known that the problem of computation of 𝜒=(G) is NP-hard in general and remains so for corona graphs. In this paper we consider the same model of coloring in the case of corona multiproducts of graphs. In particular, we obtain some results regarding the equitable chromatic number for the l-corona product G ◦l H, where G is an equitably 3- or 4-colorable graph and H is an r-partite graph, a cycle or a complete graph. Our proofs are mostly constructive in that they lead to polynomial algorithms for equitable coloring of such graph products provided that there is given an equitable coloring of G. Moreover, we confirm the Equitable Coloring Conjecture for corona products of such graphs. This paper extends the results from [H. Furmánczyk, K. Kaliraj, M. Kubale and V.J. Vivin, Equitable coloring of corona products of graphs, Adv. Appl. Discrete Math. 11 (2013) 103–120].
topic corona graph
equitable chromatic number
equitable coloring conjecture
equitable graph coloring
multiproduct of graphs
NP-completeness
polynomial algorithm.
url http://www.degruyter.com/view/j/dmgt.2017.37.issue-4/dmgt.1992/dmgt.1992.xml?format=INT
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