Signed total Roman k-domination in directed graphs

Document Type : Original paper

Authors

1 Sirjan University of Technology, Sirjan 78137, Iran

2 Lehrstuhl II fur Mathematik, RWTH Aachen University, 52056 Aachen, Germany

Abstract

Let D be a finite and simple digraph with vertex set V(D). A signed total Roman k-dominating function (STRkDF) on D is a function f:V(D){1,1,2} satisfying the conditions that (i) xN(v)f(x)k for each vV(D), where N(v) consists of all vertices of D from which arcs go into v, and (ii) every vertex u for which f(u)=1 has an inner neighbor v for which f(v)=2. The weight of an STRkDF f is ω(f)=vV(D)f(v). The signed total Roman k-domination number γstRk(D) of D is the minimum weight of an STRkDF on D. In this paper we initiate the study of the signed total Roman k-domination number of digraphs, and we present different bounds on γstRk(D). In addition, we determine the signed total Roman k-domination number of some classes of digraphs. Some of our results are extensions of known properties of the signed total Roman k-domination number γstRk(G) of graphs G.

Keywords

Main Subjects


[1] T.W. Haynes, S.T. Hedetniemi, and P.J. Slater, Domination in graphs: advanced topics, Marcel Dekker, 1998.
[2] T.W. Haynes, S.T. Hedetniemi, and P.J. Slater, Fundamentals of domination in graphs, CRC Press, 1998.
[3] M.A. Henning, Signed total domination in graphs, Discrete Math. 278 (2004), no. 1, 109–125.
[4] E. Shan and T.C.E. Cheng, Remarks on the minus (signed) total domination in graphs, Discrete Math. 308 (2008), no. 15, 3373–3380.
[5] S.M. Sheikholeslami and L. Volkmann, Signed total k-domination numbers of a directed graphs, An. St. Univ. Ovidius Constanta. 18 (2010), no. 2, 241–252.
[6] L. Volkmann, Signed total Roman k-domination in graphs, submitted.
[7] L. Volkmann, Signed total Roman domination in graphs, J. Comb. Optim. 32 (2016), no. 3, 855–871.
[8] L. Volkmann, Signed total Roman domination in digraphs, Discuss. Math. Graph Theory. 37 (2017), no. 1, 261–272.
[9] C. Wang, The signed k-domination numbers in graphs, Ars Combin. 106 (2012), 205–211.
[10] B. Zelinka, Signed total domination numbers of a graph, Czechoslovak Math. J. 51 (2001), no. 2, 225–229.