A graph $G=(V,E)$ is said to be distance magic if there is a bijection $f$ from a vertex set of $G$ to the first $|V(G)|$ natural numbers such that for each vertex $v$, its weight given by $\sum_{u \in N(v)}f(u)$ is constant, where $N(v)$ is an open neighborhood of a vertex $v$. In this paper, we introduce the concept of $p$-distance magic labeling and establish the necessary and sufficient condition for a graph to be distance magic. Additionally, we introduce necessary and sufficient conditions for a connected regular graph to exhibit distance magic properties in terms of the eigenvalues of its adjacency and Laplacian matrices. Furthermore, we study the spectra of distance magic graphs, focusing on singular distance magic graphs. Also, we show that the number of distance magic labelings of a graph is, at most, the size of its automorphism group.
This paper establishes two techniques to construct larger distance magic and (a, d)-distance antimagic graphs using Harary graphs and provides a solution to the existence of distance magicness of legicographic product and direct product of G with C4, for every non-regular distance magic graph G with maximum degree |V(G)|-1.
In this paper, we provide few results on the group distance magic labeling of lexicographic product and direct product of two graphs. We also prove some necessary conditions for a graph to be group distance magic and provide a characterization for a tree to be group distance magic.
For an arbitrary set of distances $D\subseteq \{0,1, \ldots, d\}$, a graph $G$ is said to be $D$-distance magic if there exists a bijection $f:V\rightarrow \{1,2, \ldots , v\}$ and a constant {\sf k} such that for any vertex $x$, $\sum_{y\in N_D(x)} f(y) ={\sf k}$, where $N_D(x) = \{y \in V| d(x,y) \in D\}$. In this paper we study some necessary or sufficient conditions for the existence of $D$-distance magic graphs, some of which are generalization of conditions for the existence of $\{1\}$-distance magic graphs. More specifically, we study $D$-distance magic labelings for cycles and $D$-dist…
In this paper, we determine the distance magic index of lexicograph product of a regular graph with the complement of complete graph, disjoint union of m copies of complete multi- partite graph and disjoint union of m copies of lexicographic product of cycle with complement of complete graph. In addition to that, we also prove some necessary conditions for a regular graph to be of distance magic index one.
A graph $G$ is said to be distance magic if there exists a bijection $f:V\rightarrow \{1,2, \ldots , v\}$ and a constant {\sf k} such that for any vertex $x$, $\sum_{y\in N(x)} f(y) ={\sf k}$, where $N_(x)$ is the set of all neighbours of $x$. In this paper we shall study distance magic labelings of graphs obtained from four graph products: cartesian, strong, lexicographic, and cronecker. We shall utilise magic rectangle sets and magic column rectangles to construct the labelings.
Let $Γ=(V,E)$ be a graph of order $n$. A {\em closed distance magic labeling} of $Γ$ is a bijection $\ell : V \to \{1,2, \ldots, n\}$ for which there exists a positive integer $r$ such that $\sum_{x \in N[u]} \ell(x) = r$ for all vertices $u \in V$, where $N[u]$ is the closed neighborhood of $u$. A graph is said to be {\em closed distance magic} if it admits a closed distance magic labeling. In this paper, we classify all connected closed distance magic circulants with valency at most $5$, that is, Cayley graphs $\operatorname{Cay}(\mathbb{Z}_n;S)$ where $|S| \le 5$ and $S$ generates $\mathbb{…
Hefetz, Mütze, and Schwartz conjectured that every connected undirected graph admits an antimagic orientation. In this paper we support the analogous question for distance magic labeling. Let $Γ$ be an Abelian group of order $n$. A \textit{directed $Γ$-distance magic labeling} of an oriented graph $\vec{G} = (V,A)$ of order $n$ is a bijection $\vec{l}:V \rightarrow Γ$ with the property that there is a \textit{magic constant} $μ\in Γ$ such that for every $x \in V(G)$ $ w(x) = \sum_{y \in N^{+}(x)}\vec{l}(y) - \sum_{y \in N^{-}(x)} \vec{l}(y) = μ. $ In this paper we provide an infinite family of…
AGH University of Krakow（克拉科夫AGH大学）；Andrej Marušič Institute, University of Primorska（波摩瑞大学安德烈·马鲁西奇研究所）；Institute od mathematics, physics and mechanics（数学、物理与力学研究所）
A $Γ$-distance magic labeling of a graph $G=(V,E)$ with $|V | = n$ is a bijection $\ell$ from $V$ to an Abelian group $Γ$ of order $n$ such that the weight $w(x)=\sum_{y\in N_G(x)}\ell(y)$ of every vertex $x \in V$ is equal to the same element $μ\in Γ$, called the \emph{magic constant}. A graph $G$ is called a \emph{group distance magic graph} if there exists a $Γ$-distance magic labeling for every Abelian group $Γ$ of order $|V(G)|$. In this paper we prove that some complete $k$-partite graphs are $\mathbb{Z}_p$-distance magic. Moreover we prove that $K_{m,n}$ is a group distance magic if and…
Let $G=(V,E)$ be a graph of order $n$. A closed distance magic labeling of $G$ is a bijection $\ell \colon V(G)\rightarrow \{1,\ldots ,n\}$ for which there exists a positive integer $k$ such that $\sum_{x\in N[v]}\ell (x)=k$ for all $v\in V $, where $N[v]$ is the closed neighborhood of $v$. We consider the closed distance magic graphs in the algebraic context. In particular we analyze the relations between the closed distance magic labelings and the spectra of graphs. These results are then applied to the strong product of graphs with complete graph or cycle and to the circulant graphs. We end…
Let $G=(V,E)$ be a graph of order $n$. A distance magic labeling of $G$ is a bijection $\ell \colon V\rightarrow {1,...,n}$ for which there exists a positive integer $k$ such that $\sum_{x\in N(v)}\ell (x)=k$ for all $v\in V $, where $N(v)$ is the neighborhood of $v$. We introduce a natural subclass of distance magic graphs. For this class we show that it is closed for the direct product with regular graphs and closed as a second factor for lexicographic product with regular graphs. In addition, we characterize distance magic graphs among direct product of two cycles.
A \emph{group distance magic labeling} or a $\gr$-distance magic labeling of a graph $G(V,E)$ with $|V | = n$ is an injection $f$ from $V$ to an Abelian group $\gr$ of order $n$ such that the weight $w(x)=\sum_{y\in N_G(x)}f(y)$ of every vertex $x \in V$ is equal to the same element $μ\in \gr$, called the magic constant. In this paper we will show that if $G$ is a graph of order $n=2^{p}(2k+1)$ for some natural numbers $p$, $k$ such that $°(v)\equiv c \imod {2^{p+1}}$ for some constant $c$ for any $v\in V(G)$, then there exists an $\gr$-distance magic labeling for any Abelian group $\gr$ for t…
Technical University of Ostrava（俄斯特拉发工业大学）；Institute of Mathematics, Physics and Mechanics（数学、物理与力学研究所）；University of Primorska, FAMNIT（沿海大学FAMNIT学院）；University of Ljubljana, Faculty of Education（卢布尔雅那大学教育学院）；University of Primorska, Institute Andrej Marušič（沿海大学安德烈亚·马鲁西奇研究所）
Let $G$ be a complete $k$-partite simple undirected graph with parts of sizes $p_1\le p_2...\le p_k$. Let $P_j=\sum_{i=1}^jp_i$ for $j=1,...,k$. It is conjectured that $G$ has distance magic labeling if and only if $\sum_{i=1}^{P_j} (n-i+1)\ge j{{n+1}\choose{2}}/k$ for all $j=1,...,k$. The conjecture is proved for $k=4$, extending earlier results for $k=2,3$.
A $Γ$-distance magic labeling of a graph $G=(V,E)$ with $|V | = n$ is a bijection $f$ from $V$ to an Abelian group $Γ$ of order $n$ such that the weight $w(x)=\sum_{y\in N_G(x)}f(y)$ of every vertex $x \in V$ is equal to the same element $μ\in Γ$, called the \emph{magic constant}. In this paper we will show that if $G$ is a graph of order $n=2^{p}(2k+1)$ for some natural numbers $p$, $k$ such that $°(v)\equiv c \imod {2^{p+2}}$ for some constant $c$ for any $v\in V(G)$, then there exists a $Γ$-distance magic labeling for any Abelian group $Γ$ of order $4n$ for the direct product $G\times C_4$.…
Let $G=(V,E)$ be a graph and $Γ$ an Abelian group both of order $n$. A $Γ$-distance magic labeling of $G$ is a bijection $\ell \colon V\rightarrow Γ$ for which there exists $μ\in Γ$ such that $% \sum_{x\in N(v)}\ell (x)=μ$ for all $v\in V$, where $N(v)$ is the neighborhood of $v$. Froncek %(\cite{ref_CicAus}) showed that the Cartesian product $C_m \square C_n$, $m, n\geq3$ is a $\mathbb{Z}_{mn}$-distance magic graph if and only if $mn$ is even. It is also known that if $mn$ is even then $C_m \square C_n$ has $\mathbb{Z}_α\times \mathcal{A}$-magic labeling for any $α\equiv 0 \pmod {{\rm lcm}(m,…
New Results on Difference Distance Magic Labelings
Ball State University（鲍尔州立大学）；San Francisco State University（旧金山州立大学）；Drake University（德雷克大学）；Southwestern University（西南大学）；Towson University（陶森大学）；DeSales University（迪莱萨大学）；Tarleton State University（塔勒顿州立大学）；University of Scranton（斯克兰顿大学）
For a set of distances $D$, a graph $G$ of order $n$ is said to be $D-$magic if there exists a bijection $f:V\rightarrow \{1,2, \ldots, n\}$ and a constant $k$ such that for any vertex $x$, $\sum_{y\in N_D(x)} f(y) =k$, where $N_D(x)=\{y|d(y,x)=j, j\in D\}$. In this paper we shall find sets of distances $D$s, such that the hypercube is $D-$magic. We shall utilise well-known properties of (bipartite) distance-regular graphs to construct the $D-$magic labelings.
Given a graph $G$ with $n$ vertices and an Abelian group $A$ of order $n$, an $A$-distance antimagic labelling of $G$ is a bijection from $V(G)$ to $A$ such that the vertices of $G$ have pairwise distinct weights, where the weight of a vertex is the sum (under the operation of $A$) of the labels assigned to its neighbours. An {$A$-distance magic labelling} of $G$ is a bijection from $V(G)$ to $A$ such that the weights of all vertices of $G$ are equal to the same element of $A$. In this paper we study these new labellings under a general setting with a focus on product graphs. We prove among ot…
For a set of distances $D$, a graph $G$ on $n$ vertices is said to be $D$-magic if there exists a bijection $f:V\rightarrow \{1,2, \ldots , n\}$ and a constant $k$ such that for any vertex $x$, $\sum_{y\in N_D(x)} f(y) = k$, where $N_D(x)=\{y|d(x,y)=i, i\in D\}$ is the $D$-neighbourhood set of $x$. In this paper we utilize spectra of graphs to characterize strongly regular graphs which are $D$-magic, for all possible distance sets $D$. In addition, we provide necessary conditions for distance regular graphs of diameter 3 to be $\{1\}$-magic.
A bijective mapping $f: V(G) \rightarrow \left\{1,2,\ldots,n\right\}$ is called a \emph{Distance Magic Labeling (DML) of $G$} if ~ ${\sum_{v \in N(u)}} f(v) $ is a constant for all $u\in V(G)$ where $G$ is a simple graph of order $n$ and $N(u)$ = $\{v\in V(G):$ $uv\in E(G)\}$. Graph $G$ is called a \emph{Distance Magic Graph (DMG)} if it has a DML, otherwise it is called a \emph{Non-Distance Magic (NDM) graph}. In 1996, Vilfred proposed a conjecture that cylindrical grid graphs $P_m \Box C_n$ are NDM for $m \geq 2$, $n \geq 3$ and $m,n\in\mathbb{N}$. Recently, the authors could prove the conje…
Let $G$ be a graph of order $n$ and $N = \{N(u_{i})\}^k_{i=1}$ be a sequence of neighbourhood(nbh)s in $G$ where $N(u)$ = $\{v\in V(G):$ $uv\in E(G)\}$. \emph{Nbh sequence graph $H$ of} $N$ in $G$ is defined as the union of all induced subgraphs of closed nbh $N[u_{i}]$ in $G$, $1 \leq i \leq k$, $k\in\mathbb{N}$. A labeling $f: V(G) \rightarrow \left\{1,2,\ldots,n\right\} $ is called a \emph{Distance Magic Labeling (DML)} of $G$ if ~ ${\sum_{v \in N(u)}} f(v) $ is a constant for every $u\in V(G)$. $G$ is called a \emph{Distance Magic graph (DMG)} if it has a DML, otherwise it is called a \emp…
We define a magic square to be a square matrix whose entries are nonnegative integers and whose rows, columns, and main diagonals sum up to the same number. We prove structural results for the number of such squares as a function of the size of the matrix and the line sum. We give examples for small sizes and show similar results for symmetric, pandiagonal magic squares, and magic hypercubes.
We define a labeling $f:$ $V(G)$ $\rightarrow$ $\{1, 2, \ldots, n\}$ on a graph $G$ of order $n \geq 3$ as a \emph{$k$-distance magic} ($k$-DM) if $\sum_{w\in \partial N_k(u)}{ f(w)}$ is a constant and independent of $u\in V(G)$ where $\partial N_k(u)$ = $\{v\in V(G): d(u, v) = k\}$, $k\in\mathbb{N}$. Graph $G$ is called a \emph{$k$-DM} if it has a $k$-DM labeling(L). Long Brush is a graph $G$ with $V(G)$ = $\{u_1, u_2, . . . , u_n,$ $v_1, v_2, . . . , v_{m}\}$, a path $P_n$ = $u_1$ $u_2$ . . . $u_n$ and $E(G)$ = $E(P_n)$ $\cup$ $\{u_1v_i:$ $i$ = 1 to $m\}$ $\cup$ $E(<v_1, v_2, . . . , v_{m}>)…
