n=9 k=2 b=None: COL_k holds for all star-free systems (UNSAT after 141 refinements, 7.8s)
  ... 200 refinements, 1.2s
  ... 400 refinements, 2.7s
n=9 k=3 b=None: COL_k holds for all star-free systems (UNSAT after 591 refinements, 92.0s)
  ... 200 refinements, 2.1s
  ... 400 refinements, 4.2s
  ... 600 refinements, 7.4s
  ... 800 refinements, 10.7s
  ... 1000 refinements, 18.7s
n=9 k=4 b=None: COL_k holds for all star-free systems (UNSAT after 1006 refinements, 23.6s)
  ... 200 refinements, 3.0s
  ... 400 refinements, 5.8s
  ... 600 refinements, 9.0s
  ... 800 refinements, 14.8s
  ... 1000 refinements, 20.1s
  ... 1200 refinements, 26.3s
  ... 1400 refinements, 33.4s
n=9 k=5 b=None: COL_k holds for all star-free systems (UNSAT after 1407 refinements, 33.6s)
