Graphs with odd and even distances between non-cut vertices

We prove that in a connected graph, the distances between non-cut vertices are odd if and only if it is the line graph of a strong unique independence tree. We then show that any such tree can be inductively constructed from stars using a simple operation. Further, we study the connected graphs in w...

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Bibliographic Details
Main Authors: Kateryna Antoshyna, Sergiy Kozerenko
Format: Article
Language:English
Published: AGH Univeristy of Science and Technology Press 2024-12-01
Series:Opuscula Mathematica
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Online Access:https://www.opuscula.agh.edu.pl/vol45/1/art/opuscula_math_4501.pdf
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Summary:We prove that in a connected graph, the distances between non-cut vertices are odd if and only if it is the line graph of a strong unique independence tree. We then show that any such tree can be inductively constructed from stars using a simple operation. Further, we study the connected graphs in which the distances between non-cut vertices are even (shortly, NCE-graphs). Our main results on NCE-graphs are the following: we give a criterion of NCE-graphs, show that any bipartite graph is an induced subgraph of an NCE-graph, characterize NCE-graphs with exactly two leaves, characterize graphs that can be subdivided to NCE-graphs, and provide a characterization for NCE-graphs which are maximal with respect to the edge addition operation.
ISSN:1232-9274