Vertex-magic total labelings of disconnected graph

Let G be a graph with vertex set \(V = V (G)\) and edge set \(E = E(G)\) and let \(e = |E(G)|\) and \(v = |V (G)|\). A one-to-one map \(λ\) from \(V ∪ E\) onto the integers \(\{1, 2, …, v + e\}\) is called vertex magic total labeling if there is a constant \(k\) so that for every vertex \(x\), \(λ+\sum λ(xy)=k\). where the sum is over all vertices \(y\) adjacent to \(x\). Let us call the sum of labels at vertex x the weight \(w_{λ}(x)\) of the vertex under labeling \(λ\); we require \(w_{λ}(x) = k\) for all \(x\). The constant \(k\) is called the magic constant for \(λ\). In this paper, we present the vertex magic total labelings of disconnected graph, in particular, two copies of isomorphic generalized Petersen graphs \(2P(n, m)\), disjoint union of two non-isomorphic suns \(S_{m} ∪ S_{n}\) and t copies of isomorphic suns \(tS_{n}\).