• bicliques;
  • biclique graphs;
  • clique graphs;
  • divergent graphs;
  • iterated graph operators;
  • graph dynamics


A biclique of a graph G is a maximal induced complete bipartite subgraph of G. The biclique graph of G, denoted by inline image, is the intersection graph of the bicliques of G. We say that a graph G diverges (or converges or is periodic) under an operator F whenever inline image (inline image for some m, or inline image for some k and inline image, respectively). Given a graph G, the iterated biclique graph of G, denoted by inline image, is the graph obtained by applying the biclique operator k successive times to G. In this article, we study the iterated biclique graph of G. In particular, we classify the different behaviors of inline image when the number of iterations k grows to infinity. That is, we prove that a graph either diverges or converges under the biclique operator. We give a forbidden structure characterization of convergent graphs, which yield a polynomial time algorithm to decide if a given graph diverges or converges. This is in sharp contrast with the situsation for the better known clique operator, where it is not even known if the corresponding problem is decidable. © 2012 Wiley Periodicals, Inc. J. Graph Theory 73: 181–190, 2013