lower bound = 40

40 ≤ CC(12,6,4) ≤ 41

Method of Construction: nurmela and ostergard simulated annealing cover

Lower Bound: Schonheim

  1  2  3  4  5  6
  1  2  3  7  8  9
  4  5  6  7  8  9
  2  3  5  7  8 10
  1  4  6  7  8 10
  2  3  4  7  9 10
  1  5  6  7  9 10
  1  4  5  8  9 10
  2  3  6  8  9 10
  1  3  5  7  8 11
  2  4  6  7  8 11
  1  3  4  7  9 11
  2  5  6  7  9 11
  2  4  5  8  9 11
  1  3  6  8  9 11
  3  4  5  7 10 11
  1  2  6  7 10 11
  1  2  4  8 10 11
  3  5  6  8 10 11
  1  2  5  9 10 11
  3  4  6  9 10 11
  1  2  4  5  7 12
  1  2  5  6  8 12
  3  4  6  7  8 12
  1  2  4  6  9 12
  3  5  6  7  9 12
  3  4  5  8  9 12
  2  4  5  6 10 12
  1  3  6  7 10 12
  1  3  4  8 10 12
  1  3  5  9 10 12
  2  7  8  9 10 12
  1  4  5  6 11 12
  2  3  6  7 11 12
  2  3  4  8 11 12
  2  3  5  9 11 12
  1  7  8  9 11 12
  1  2  3 10 11 12
  5  7  8 10 11 12
  4  7  9 10 11 12
  6  8  9 10 11 12