Covering all cliques of a graph
Discrete Mathematics - Topics on domination
Journal of Graph Theory
On the annihilation number of a graph
AMATH'09 Proceedings of the 15th american conference on Applied mathematics
Locating and total dominating sets in trees
Discrete Applied Mathematics
Bounds on the locating-total domination number of a tree
Discrete Applied Mathematics
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A set S of vertices in a graph G is a total dominating set if every vertex of G is adjacent to some vertex in S. The total domination number @c"t(G) is the minimum cardinality of a total dominating set in G. The annihilation number a(G) is the largest integer k such that the sum of the first k terms of the non-decreasing degree sequence of G is at most the number of edges in G. In this paper, we investigate relationships between the annihilation number and the total domination number of a graph. Let T be a tree of order n=2. We show that @c"t(T)@?a(T)+1, and we characterize the extremal trees achieving equality in this bound.