In many clique search algorithms well coloring of the nodes is employed to find an upper bound of the clique number of the given graph. In an earlier work a non-traditional edge coloring scheme was proposed to get upper bounds that are typically better than the one provided by the well coloring of the nodes. In this paper we will show that the same scheme for well coloring of the edges can be used to find lower bounds for the clique number of the given graph. In order to assess the performance of the procedure we carried out numerical experiments.
Çatalzurek, Ü. V., Feo, J., Gebremedhin, A. H., Halappanavar, M., and Pothen, A. Graph coloring algorithms for multi-core and massively multi threaded architectures. Parallel Comp. 38 (2012), 576–594.
Leighton, F. T.A graph coloring algorithm for large scheduling problems. Journal of Research of National Bureau of Standards 84 (1979), 489–506.
Matula, D. W., Marble, G., and Isaacson, J. Graph coloring algorithms. In Graph Theory and Computing, R. Read, Ed Academic Press, 1972, pp. 109–122.
Papadimitriou, C. H. Computational Complexity. Addison-Wesley Publishing Company, Inc., Reading, MA, 1994.
Sloane, N. J. A. Challenge problems: Independent sets in graphs. http://neilsloane.com/doc/graphs.html.
Szabo, S. Parallel algorithms for finding cliques in a graph. Journal of Physics, Conference Series 268 (2011), 012030. doi:.
Szabo, S. Monoton matrices and finding cliques in a graph. Annales Univ. Sci. Budapest., Sect. Computatorica 41 (2013), 307–322.
Weisstein, E. W. Monotonic matrix. in MathWorld–A Wolfram Web Resource.