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Discussiones Mathematicae Graph Theory 32(3) (2012)
461-471
DOI: https://doi.org/10.7151/dmgt.1618
The Total {k}-domatic Number of Digraphs
Seyed Mahmoud Sheikholeslami
Department of Mathematics | Lutz Volkmann
Lehrstuhl II für Mathematik |
Abstract
For a positive integer k, a total {k}-dominating function of a digraph D is a function f from the vertex set V(D) to the set {0,1,2, …,k} such that for any vertex v ∈ V(D), the condition ∑u ∈ N −(v)f(u) ≥ k is fulfilled, where N −(v) consists of all vertices of D from which arcs go into v. A set {f1,f2, …,fd} of total {k}-dominating functions of D with the property that ∑i = 1dfi(v) ≤ k for each v ∈ V(D), is called a total {k}-dominating family (of functions) on D. The maximum number of functions in a total {k}-dominating family on D is the total {k}-domatic number of D, denoted by dt{k}(D). Note that dt{1}(D) is the classic total domatic number dt(D). In this paper we initiate the study of the total {k}-domatic number in digraphs, and we present some bounds for dt{k}(D). Some of our results are extensions of well-know properties of the total domatic number of digraphs and the total {k}-domatic number of graphs.
Keywords: digraph, total {k}-dominating function, total {k}-domination number, total {k}-domatic number
2010 Mathematics Subject Classification: 05C69.
References
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Received 31 March 2011
Revised 29 August 2011
Accepted 30 August 2011
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