On coloring graphs with well-distributed edge density

Fuente: arXiv
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Hauptverfasser: Hassan, Syed Mujtaba, Hussain, Shahid
Format: Preprint
Veröffentlicht: 2024
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author Hassan, Syed Mujtaba
Hussain, Shahid
author_facet Hassan, Syed Mujtaba
Hussain, Shahid
contents In this paper, we introduce a class of graphs which we call average hereditary graphs. Many graphs that occur in the usual graph theory applications belong to this class of graphs. Many popular types of graphs fall under this class, such as regular graphs, trees and other popular classes of graphs. The paper aims to explore some interesting properties regarding colorings average hereditary graphs. We prove a new upper bound for the chromatic number of a graph in terms of its maximum average degree and show that this bound is an improvement on previous bounds. From this, we show a relationship between the average degree and the chromatic number of an average hereditary graph. We then show that even with new bound, the graph 3-coloring problem remains NP-hard when the input is restricted to average hereditary graphs. We provide an equivalent condition for a graph to be average hereditary, through which we show that we can decide if a given graph is average hereditary in polynomial time.
format Preprint
id arxiv_https___arxiv_org_abs_2402_06803
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On coloring graphs with well-distributed edge density
Hassan, Syed Mujtaba
Hussain, Shahid
Discrete Mathematics
Computational Complexity
Combinatorics
05C15, 05C42, 05C07 (Primary) 05C75, 05C69, 05C25 (Secondary)
In this paper, we introduce a class of graphs which we call average hereditary graphs. Many graphs that occur in the usual graph theory applications belong to this class of graphs. Many popular types of graphs fall under this class, such as regular graphs, trees and other popular classes of graphs. The paper aims to explore some interesting properties regarding colorings average hereditary graphs. We prove a new upper bound for the chromatic number of a graph in terms of its maximum average degree and show that this bound is an improvement on previous bounds. From this, we show a relationship between the average degree and the chromatic number of an average hereditary graph. We then show that even with new bound, the graph 3-coloring problem remains NP-hard when the input is restricted to average hereditary graphs. We provide an equivalent condition for a graph to be average hereditary, through which we show that we can decide if a given graph is average hereditary in polynomial time.
title On coloring graphs with well-distributed edge density
topic Discrete Mathematics
Computational Complexity
Combinatorics
05C15, 05C42, 05C07 (Primary) 05C75, 05C69, 05C25 (Secondary)
url https://arxiv.org/abs/2402.06803