On the domination number of generalized Petersen graphs P(n,2)P(n,2)

Let G=(V(G),E(G))G=(V(G),E(G)) be a graph. A set S⊆V(G)S⊆V(G) is a dominating set if every vertex of V(G)−SV(G)−S is adjacent to some vertex in SS. The domination number γ(G)γ(G) of GG is the minimum cardinality of a dominating set of GG. In this paper, we study the domination number of generalized Petersen graphs P(n,2)P(n,2) and prove that γ(P(n,2))=n−⌊n5⌋−⌊n+25⌋.