Codice QDD 22 Titolo Orthogonal double covers of complete bipartite graphs by the union of a cycle and a star Data 2007-09-14 Autore/i Higazy, M. Sh. ; El-Shanawany, R. ; Scapellato, R. Pubblicato Australas. J. Combin., v. 43 (2009), pp. 281-293. Abstract Let H be a graph on n vertices and C a collection of subgraphs of H, one for each vertex. Then C is an orthogonal double cover (ODC) of H if every edge of H occurs in exactly two members of C and any two members of C share exactly an edge whenever the corresponding vertices are adjacent in H. If all subgraphs in C are isomorphic to a given spanning subgraph G, then C is said to be an ODC of H by G. We construct ODCs of complete bipartite graphs by the union of a cycle and a star, that can be either disjoint or have in common the center of the star.