Fractional domination of strong direct products (Q1324692)

The domination number of a graph \(G\), \(\gamma(G)\), is the minimum size of a set \(A\) of vertices of \(G\) such that each vertex of \(G\) is either in \(A\) or is adjacent to an element of \(A\). Vizing conjectured that \(\gamma (G \oplus H) = \gamma (G) \cdot \gamma (H)\), where \(G \oplus H\) is the Cartesian product of \(G\) and \(H\). In the paper an analogous result for fractional domination numbers is proved.