1 Departament d'Enginyeria Informàtica i Matemàtiques
2 Faculty of Electrical Engineering and Computer Science
3 DEPARTAMENTO DE MATEMATICAS
A graph G is an efficient open domination graph if there exists a subset D of V(G) for which the open neighborhoods centered in vertices of D form a partition of V(G). We completely describe efficient open domination graphs among lexicographic, strong, and disjunctive products of graphs. For the Cartesian product we give a characterization when one factor is K2.