Cross‐intersecting couples of graphs
Emanuela Fachini, János Körner · Journal of Graph Theory · 2007
Abstract Two graphs on the same vertex set form a cross‐intersecting couple if they have a pair of clique coverings with the property that every pair of cliques from the respective coverings intersect. In particular, a graph is called normal if it forms a cross‐intersecting couple with its complement. We determine the largest size of families of graphs every pair of which forms a cross‐intersecting couple under various additional restrictions. © 2007 Wiley Periodicals, Inc. J Graph Theory 56: 105–112, 2007