RT journal article T1 Triple Roman domination in graphs A1 Abdollahzadeh Ahangar, H. A1 Álvarez Ruiz, María del Pilar A1 Chellali, M. A1 Sheikholeslami, S.M. A1 Valenzuela Tripodoro, Juan Carlos A2 Estadística e Investigación Operativa A2 Matemáticas K1 Roman domination K1 domination K1 double Roman domination K1 triple Roman domination AB The Roman domination in graphs is well-studied in graph theory. The topic is related to a defensive strategy problem in which the Roman legions are settled in some secure cities of the Roman Empire. The deployment of the legions around the Empire is designed in such a way that a sudden attack on any undefended city could be quelled by a legion from a strong neighbour. There is an additional condition: no legion can move if doing so leaves its base city defenceless. In this manuscript, we start the study of a variant of Roman domination in graphs: triple Roman domination. We consider that any city of the Roman Empire must be able to be defended by at least three legions. These legions should be either in the attacked city or in one of its neighbours. We determine various bounds on the triple Roman domination number for general graphs, and we give exact values for some graph families. Moreover, complexity results are also obtained. PB Elsevier Inc. SN 0096-3003 YR 2021 FD 2021-02-15 LK http://hdl.handle.net/10498/30712 UL http://hdl.handle.net/10498/30712 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 10-may-2026