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A note on Hameed's conjecture on the semi-transitivity of Mycielski graphs Full article

Journal Discussiones Mathematicae - Graph Theory
ISSN: 1234-3099 , E-ISSN: 2083-5892
Output data Year: 2025, DOI: 10.7151/dmgt.2575
Tags semi-transitive graph, semi-transitive orientation, word-representable graph, Mycielski graph, extended Mycielski graph
Authors Kitaev Sergey 1 , Pyatkin Artem V. 2,3
Affiliations
1 Department of Mathematics and Statistics University of Strathclyde
2 Sobolev Institute of Mathematics
3 Novosibirsk State University

Funding (1)

1 Sobolev Institute of Mathematics FWNF-2022-0019

Abstract: An orientation of a graph is semi-transitive if it contains no directed cycles and has no shortcuts. An undirected graph is semi-transitive if it can be oriented in a semi-transitive manner. The class of semi-transitive graphs includes several important graph classes. The Mycielski graph of an undirected graph is a larger graph constructed in a specific manner, which maintains the property of being triangle-free but increases the chromatic number. In this note, we prove Hameed’s conjecture, which states that the Mycielski graph of a graph G is semi-transitive if and only if G is a bipartite graph. Notably, our solution to the conjecture provides an alternative and shorter proof of the Hameed’s result on a complete characterization of semitransitive extended Mycielski graphs.
Cite: Kitaev S. , Pyatkin A.V.
A note on Hameed's conjecture on the semi-transitivity of Mycielski graphs
Discussiones Mathematicae - Graph Theory. 2025. DOI: 10.7151/dmgt.2575 WOS РИНЦ OpenAlex
Dates:
Submitted: Oct 7, 2024
Accepted: Jan 4, 2025
Published online: Jan 20, 2025
Identifiers:
Web of science: WOS:001401990000001
Elibrary: 81759176
OpenAlex: W4406677866
Citing: Пока нет цитирований
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