Randomly orthogonal factorizations in networks

Let m, r, k be three positive integers. Let G be a graph with vertex set V(G) and edge set E(G), and let f: V(G) → N be a function such that f ( x ) ≥ ( k + 2 ) r − 1 for any x ∈ V(G). Let H1, H2, … , Hk be k vertex disjoint mr-subgraphs of a graph G. In this paper, we prove that every ( 0 , m f − ( m − 1 ) r ) -graph admits a (0, f)-factorization randomly r-orthogonal to each Hi ( i = 1 , 2 , … , k ).