(Total) Domination in Prisms

  • Jernej Azarija
  • Michael Henning
  • Sandi Klavžar
Keywords: Domination, Total domination, Hypercube, Cartesian product of graphs, Covering codes, Hypergraph transversal


Using hypergraph transversals it is proved that $\gamma_t(Q_{n+1}) = 2\gamma(Q_n)$, where $\gamma_t(G)$ and $\gamma(G)$ denote the total domination number and the domination number of $G$, respectively, and $Q_n$ is the $n$-dimensional hypercube. More generally, it is shown that if $G$ is a bipartite graph, then $\gamma_t(G \square K_2) = 2\gamma(G)$. Further, we show that the bipartiteness condition is essential by constructing, for any $k \ge 1$, a (non-bipartite) graph $G$ such that $\gamma_t(G\square K_2) = 2\gamma(G) - k$. Along the way several domination-type identities for hypercubes are also obtained.
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