# A note on Roman $k$-tuple domination number

Document Type : Short notes

Authors

1 Universiti Sains Malaysia

2 Shahed University

Abstract

‎‎For an integer $k\geq 2$‎, ‎a Roman $k$-tuple dominating function‎, ‎(or just RkDF)‎, ‎in a graph $G$ is a function $f \colon V(G) \rightarrow \{0‎, ‎1‎, ‎2\}$ satisfying the condition that every vertex $u$ for which $f(u) = 0$ is adjacent to at least $k$ vertices $v$ for which $f(v) = 2$‎, ‎and every vertex $u$ for which $f(u) \neq 0$ is adjacent to at least $k-1$ vertices $v$ for which $f(v) = 2$‎. ‎The Roman $k$-tuple domination number of ‎$‎G‎$‎‎ ‎is the minimum weight of an RkDF in $G$. ‎In this note we settle two problems posed in [Roman $k$-tuple Domination in Graphs‎, ‎Iranian J‎. ‎Math‎. ‎Sci‎. ‎Inform‎. ‎15 (2020)‎, ‎101--115]‎.

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#### References

[1] H. Abdollahzadeh Ahangar, M.A. Henning, V. Samodivkin, and I.G. Yero, Total Roman domination in graphs, Appl. Anal. Discrete Math. 10 (2016), no. 2, 501–517.
[2] M. Chellali, N. Jafari Rad, S.M. Sheikholeslami, and L. Volkmann, Roman domination in graphs, Topics in Domination in Graphs, Springer, 2020, pp. 365–409.
[3] E.J. Cockayne, P.A. Dreyer Jr, S.M. Hedetniemi, and S.T. Hedetniemi, Roman domination in graphs, Discrete Math. 278 (2004), no. 1-3, 11–22.
[4] A P Kazemi, Roman k-tuple domination in graphs, Iranian Journal of Mathematical Sciences and Informatics 15 (2020), no. 2, 101–115.