A dominating set of a graph G =(V (G),E(G)) is a set S ⊆ V (G) such that every vertex of G belongs to S or is adjacent to at least one vertex in S.T h edominating set problem consists of determining the minimum number of vertices in a dominating set of G.M a n y real-world applications can be modelled as dominating set problems and some of then led to the appearance of variants of the original problem. A dominating clique set is a dominating set that is also a clique. The dominating clique problem consists of determining the minimum number of vertices in a dominating clique set of a graph G.I n 1 9 7 7 , Cockayne and Hedetniemi [41] defined a domatic partition of a graph G =(V (G),E(G)) as a partition of V (G) in dominating sets. The domatic partition problem consists of determining the maximum number of parts in a domatic partition of a graph. A natural extension of this problem consists of considering partitions of V (G) in dominating sets with aditional properties. In particular, a clique domatic partition is a partition of V (G) into dominating clique sets; and the clique domatic partition problem,t h ep r o b l e mo f determining the clique domatic number of G, d cl (G):=max{|P| : P is a clique domatic partition of G},w h e nG has at least one clique domatic partition.In this work, we approach the dominating clique problem and the clique domatic partition problem. For the dominating clique problem we review some existing results in the literature and formulate a conjecture, which establishes a sufficient condition for the existence of a dominating clique set in a graph. On the clique domatic partition problem, we obtain results in some classes of graphs. In particular, we characterize the bipartite graphs and powers of cycles which have clique domatic partitions and for these graphs we determine the clique domatic number. Similar results are also obtained for the class of graphs generated by the cartesian product operation and the class of graphs generated by the direct product of complete graphs. ix x
ResumoUm conjunto dominante em um grafo G =( V (G),E(G)) é um conjunto S ⊆ V (G), tal que todo vértice do grafo, ou pertence a S, ou é adjacente a pelo menos um elemento de S.Oproblema do conjunto dominante consiste em determinar a cardinalidade de um conjunto dominante mínimo em um grafo G. Muitas aplicações podem ser modeladas como problemas de conjuntos dominantes e algumas delas levaram ao surgimento de variantes do problema original. O problema da clique-dominante consiste em determinar ac a r d i n a l i d a d ed eu mc o n j u n t oc l i q u e -d o m i n a n t em í n i m oe mu mg r a f oG. Um conjunto clique-dominante é um conjunto dominante que tem a propriedade adicional de ser uma clique. Em 1977, Cockayne e Hedetniemi [41] definiram uma partição dominante de um grafo G =( V (G),E(G)) como uma partição de V (G) em conjuntos dominantes. O problema da partição dominante consiste em determinar a cardinalidade máxima de uma partição dominante. Uma extensão natural deste problema consiste em considerar par...