On the Index Set of Complete Multipartite Graphs

Document Type : Original Research Article

Author

Semnan Branch, Islamic Azad University, Semnan, Iran

Abstract

For every natural number $h$, a graph $G$ is said to be $h$-magic if there exists a labeling $l:E(G)\longrightarrow {Z}_h\setminus \{ 0 \}$ such that the labeling $l^+:V(G)\longrightarrow Z_{h}$ defined by $$l^+(v)=\sum_{uv\in E(G)} l(uv), $$ is a constant map. A constant of a magic sum is called an index of $G$, an index for short, and we write ${\rm I}_{A}(G)=\{r: \hspace{.1cm} G \hbox{ is } A\hbox{-magic with index } r\}$. Let $G$ be a graph and $A$ be an abelian group. A graph $G$ is called $A$-magic if there exists an edge labeling $l:E(G)\longrightarrow A\setminus \{ 0 \}$ such that the induced vertex set labeling $l^+:V(G)\longrightarrow A$, defined by $l^+(v)=\sum_{uv\in E(G)} l(uv)$, where the sum is over all $e\in E(G)$ incident with $v$, is a constant map. A constant of a magic sum is called an index of $G$, an index for short, and we write ${\rm I}_{A}(G)=\{r: \hspace{.1cm} G \hbox{ is } A\hbox{-magic with index } r\}$. In 2011 Shiu and Low proved that $0\in {\rm I}_{A}(K_{n_{1},\ldots,n_{t}})$, where $n_{i}\geq2$ ($i=1,\ldots,t$). For an undirected graph G, and an abelian group A, an A-magic labelling is an assignment of non-zero element of A, to the edges of G, such that the sum of the values of all edges incident with each vertex is constant. A constant on magic sum is called an index set of G. In this paper, for $t\geq2$ we determine the index set of the complete multipartite graph $K_{n_{1},\ldots,n_{t}}$, where $n_{i}\geq2$ (for $i=1,\ldots,t$).

Keywords


1. S. Akbari, A. Daemi, O. Hatami Javanmard, A. Mehrabian, Zero-sum folows in regular graphs, Graphs and Combinatoris  26, 603-615 (2010).
2. S. Akbari and S. Bahramian, On the null set of complete multipartite graphs, Electronic Notes in Discrete Mathematics, Vol. 45 , 67-72, (2014).
3. R. Chandrasekaran, M. Dawande, M. Baysan, On a labeling problem in graphs, Discrete Applied Mathematics, 159, 746-759, (2011).
4. A.G. Chetwynd, A.J.W. Hilton, Regular graphs of high degree are 1-factorizable, Proceedings of London Mathematical Society 50(2), 193-206, (1985).
5. B. Freyberg, Face-Magic Labelings of Some Grid-Related Graphs, Communications in Combinatorics and Optimization, Vol. 8, No. 3 , pp. 595-601, (2023)
6. A. Farida, R.P. Indah, N.A. Sudibyo, Magic covering and edge magic labelling and its application, Journal of Physics Conference Series, 1657 (2020) 012051.
7. M.J. Nikmehr, S. bahramian, Group magicness of certain planar Graphs, Transactions on Combinatorics, Vol. 3, 1-9, (2014).
8. E. Salehi, Zero-sum magic graphs and their null sets, Ars Combinatoria, 82, 41-53(2007).
9. E. Salehi, On zero-sum magic graphs and their null set, Bulletin of Institute of Mathematics, Academia Sinca 3, 225-264 (2008).
10. J. Sedlaced, On magic graphs, Math. Slov, 26(1976), 329-335.
11. J. Sedlaced, Some properties of magic graphs, in Graphs, Hypergraph, and Bloc Syst. 1976, Proc. Symp. Comb. Anal, Zielona Gora (1976), 247-253.
12. W.C. Shiue and Richard M. Low, Group magicness of complete n-partite graphs, JCMCC, 58(2006) 129-134.
13. T.M. Wang, C.M. Lin, Magic sum spectra of group magic graphs, India-Taiwan Conference on Discrete Mathematics, NTU, November 9-12, 2009.
14. W.D. Wallis, Magic Gaphs, Birkhauser Boston, (2001).
Volume 8, Issue 2
December 2023
Pages 153-159
  • Receive Date: 14 January 2025
  • Revise Date: 12 February 2025
  • Accept Date: 17 February 2025
  • Publish Date: 01 December 2024