On $\gamma$-free, $\gamma$-totally-free and $\gamma$-fixed sets in graphs

Document Type : Original paper

Authors

1 Department of Mathematics, S. D. College, Alappuzha-690 104

2 DOS in Mathematics Manasagangotri

3 Director (n-CARDMATH) Kalasalingam University Anand Nagar, Krishnankoil-626 126 Tamil Nadu, India

Abstract

Let $G=(V,E)$ be a connected graph. A subset $S$ of $V$ is called a $\gamma$-free set if there exists a $\gamma$-set $D$ of $G$ such that $S \cap D= \emptyset$. If further the induced subgraph $H=G[V-S]$ is connected, then $S$ is called a  $cc$-$\gamma$-free set of $G$. We use this concept to identify connected induced subgraphs $H$ of a given graph $G$ such that $\gamma(H) \leq \gamma(G)$. We also introduce the concept of $\gamma$-totally-free and $\gamma$-fixed sets and present several basic results on the corresponding parameters. 

Keywords


[1] G. Chartrand, L. Lesniak, and P. Zhang, Graphs & digraphs, CRC, Boca Raton, 2016.
[2] T.W. Haynes, S.T. Hedetniemi, and P.J. Salter, Fundamentals of Domination in Graphs, Marcel Dekker, New York, 1998.
[3] S.M. Hedetniemi, S.T. Hedetniemi, and R. Reynolds, Combinatorial problems on chessboards: II, Domination in Graphs, Advanced Topics (T.W. Haynes, S.T. Hedetniemi, and P.J. Salter, eds.), Marcel Dekker, Inc., New York, 1998, pp. 133–
192.
[4] N. Jafari Rad, D.A. Mojdeh, R. Musawi, and E. Nazari, Total domination in cubic knödel graphs, Commun. Comb. Optim. 6 (2021), no. 2, 221–230.
[5] E. Sampathkumar and P.S. Neeralagi, Domination and neighbourhood critical, fixed, free and totally free points, Indian J. Statistics (1992), 403–407.