Signed total Italian k-domination

Document Type : Original paper

Author

College of Science, China Jiliang University, Hangzhou 310018, China

Abstract

Let k1 be an integer. A signed total Italian k-dominating function (STIkDF) on a graph G=(V,E) is a function f:V{1,1,2} satisfying the conditions that uN(v)f(u)k for each vertex vV, where N(v) is the neighborhood of v, and each vertex u with f(u)=1 is adjacent to a vertex v with f(v)=2 or to two vertices w and z with f(w)=f(z)=1. The weight of an STIkDF f is w(f)=vVf(v). The signed total Italian k-domination number of G, denoted by γstIk(G), is the minimum weight of an STIkDF on G. In this paper, we prove that the decision problem for the signed total k-domination is NP-complete for k{1,2}. We present tight lower bound on \textcolor{red}{γstI2(G)}, and characterize all extremal graphs. Using a discharging method, we also determine the value \textcolor{red}{γstI2(C3Cn)} for all n3.

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Main Subjects


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