
arXiv: 1907.07866
handle: 20.500.12556/RUL-163136 , 11454/79060
The 2-domination number $��_2(G)$ of a graph $G$ is the minimum cardinality of a set $ D \subseteq V(G) $ for which every vertex outside $ D $ is adjacent to at least two vertices in $ D $. Clearly, $ ��_2(G) $ cannot be smaller than the domination number $ ��(G) $. We consider a large class of graphs and characterize those members which satisfy $��_2=��$. For the general case, we prove that it is NP-hard to decide whether $��_2=��$ holds. We also give a necessary and sufficient condition for a graph to satisfy the equality hereditarily.
Submitted to a journal in July 2018
computational complexity, 2-domination number, 05C69, 05C75, 68Q25, Analysis of algorithms and problem complexity, domination number, K-Domination, Annihilation Number, info:eu-repo/classification/udc/519.17, Vertex subsets with special properties (dominating sets, independent sets, cliques, etc.), Bounds, Transversal Numbers, QA1-939, FOS: Mathematics, Mathematics - Combinatorics, Structural characterization of families of graphs, Combinatorics (math.CO), Graphs, Mathematics, hereditary property
computational complexity, 2-domination number, 05C69, 05C75, 68Q25, Analysis of algorithms and problem complexity, domination number, K-Domination, Annihilation Number, info:eu-repo/classification/udc/519.17, Vertex subsets with special properties (dominating sets, independent sets, cliques, etc.), Bounds, Transversal Numbers, QA1-939, FOS: Mathematics, Mathematics - Combinatorics, Structural characterization of families of graphs, Combinatorics (math.CO), Graphs, Mathematics, hereditary property
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