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Bounds on a Generalized Total Domination Parameter

Michael A. Henning1, Henda C. Swart2
1University of Zululand
2University of Natal.

Abstract

If \(n\) is an integer, \(n \geq 2\), and \(u\) and \(v\) are vertices of a graph \(G\), then \(u\) and \(v\) are said to be \(K_n\)-adjacent vertices of \(G\) if there is a subgraph of \(G\), isomorphic to \(K_n\), containing \(u\) and \(v\). A total \(K_n\)-dominating set of \(G\) is a set \(D\) of vertices such that every vertex of \(G\) is \(K_n\)-adjacent to a vertex of \(D\). The total \(K_n\)-domination number \(\gamma_{K_n}^t(G)\) of \(G\) is the minimum cardinality among the total \(K_n\)-dominating sets of vertices of \(G\). It is shown that, for \(n \in \{3, 4, 5\}\), if \(G\) is a graph with no \(K_n\)-isolated vertex, then \(\gamma_{K_n}^t(G) \leq (2p)/{n}\). Further, \(K_n\)-connectivity is defined and it is shown that, for \(n \in \{3, 4\}\), if \(G\) is a \(K_n\)-connected graph of order \(\geq n + 1\), then \(\gamma_{K_n}^t(G) \leq (2p)/(n + 1)\). We establish that the upper bounds obtained are best possible.