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 2023): 0.5

5-year Journal Impact Factor (2023): 0.6

CiteScore (2023): 2.2

SNIP (2023): 0.681

Discussiones Mathematicae Graph Theory

Article in volume


Authors:

P. Dorbec

Paul Dorbec

Normandie Univ, UNICAEN,
ENSICAEN, CNRS, GREYC

email: paul.dorbec@unicaen.fr

0009-0007-1179-6082

F. Kaci

Fatma Kaci

Biskra University

email: fatma.kaci@univ-biskra.dz

0000-0001-5019-7663

Title:

Disjoint maximal independent sets in graphs and hypergraphs

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Source:

Discussiones Mathematicae Graph Theory 44(4) (2024) 1361-1371

Received: 2023-01-27 , Revised: 2023-05-05 , Accepted: 2023-05-05 , Available online: 2023-06-07 , https://doi.org/10.7151/dmgt.2500

Abstract:

In this paper, we consider the question of the existence of disjoint maximal independent sets (\MIS) in graphs and hypergraphs. The question was raised in the 1970's independently by Berge and Payan. They considered the question of characterizing the graphs that admit disjoint \MIS, and in particular whether regular graphs do. In this paper, we are interested in the existence of disjoint \MIS\ in a graph or in its complement, motivated by the fact that most constructions of graphs that do not admit disjoint \MIS\ are such that their complement does. We prove that there are disjoint \MIS\ in a graph or its complement whenever the graph has diameter at least three or has chromatic number at most four. We also define a graph of chromatic number 5 and diameter 2 which does not admit disjoint \MIS\ nor its complement. As our work was first motivated by a more recent work on disjoint \MIS\ in hypergraphs by Acharya (2010), we also consider the question of the existence of disjoint \MIS\ in hypergraphs. We answer a question by Jose and Tuza (2009), proving that there exists balanced $k$-connected hypergraphs admitting no disjoint \MIS.

Keywords:

maximal independent set, clique, disjoint sets

References:

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