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 2022): 0.7

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CiteScore (2022): 1.9

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Discussiones Mathematicae Graph Theory

Article in volume


Authors:

Š. Miklavič

Štefko Miklavič

University of Primorska

email: stefko.miklavic@upr.si

P. Šparl

Primoz Šparl

University of Ljubljana, Faculty of Education, Kardeljeva ploscad 16, 1000 Ljubljana

email: primoz.sparl@pef.uni-lj.si

Title:

On distance magic labelings of Hamming graphs and folded hypercubes

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Source:

Discussiones Mathematicae Graph Theory 44(1) (2024) 17-33

Received: 2021-06-01 , Revised: 2021-09-01 , Accepted: 2021-09-01 , Available online: 2021-09-13 , https://doi.org/10.7151/dmgt.2430

Abstract:

Let $Γ=(V,E)$ be a graph of order $n$. A distance magic labeling of $Γ$ is a bijection $\ell \colon V \to \{1,2, \ldots, n\}$ for which there exists a positive integer $k$ such that $\sum_{x \in N(u)} \ell(x) = k$ for all vertices $u \in V$, where $N(u)$ is the neighborhood of $u$. A graph is said to be distance magic if it admits a distance magic labeling. The Hamming graph $\mathrm{H}(D,q)$, where $D, q$ are positive integers, is the graph whose vertex set consists of all words of length $D$ over an alphabet of size $q$ in which two vertices are adjacent whenever the corresponding words differ in precisely one position. The well-known hypercubes are precisely the Hamming graphs with $q = 2$. Distance magic hypercubes were classified in two papers from 2013 and 2016. In this paper we consider all Hamming graphs. We provide a sufficient condition for a Hamming graph to be distance magic and as a corollary provide an infinite number of pairs $(D, q)$ for which the corresponding Hamming graph $\mathrm{H}(D,q)$ is distance magic. A folded hypercube is a graph obtained from a hypercube by identifying pairs of vertices at maximal distance. We classify distance magic folded hypercubes by showing that the dimension-$D$ folded hypercube is distance magic if and only if $D$ is divisible by $4$.

Keywords:

distance magic labeling, distance magic graph, Hamming graph, folded hypercube

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