On the total k-domination number of graphs
Let k be a positive integer and let G = (V,E) be a simple graph. The k-tuple domination number of G is the minimum cardinality of a k-tuple dominating set S, a set that for every vertex v ∈ V, . Also the total k-domination number of G is the minimum cardinality of a total k -dominating set S, a set that for every vertex v ∈ V, . The k-transversal number τₖ(H) of a hypergraph H is the minimum size of a subset S ⊆ V(H) such that |S ∩e | ≥ k for every edge e ∈ E(H). We know that for any graph...