“…0),(1,1),(1,2)}. The sons of S 12 are:• S 18 = S 12 ∪ {(0, 1)} \ {(2, 1)} = N 2 \ {(1, 0), (2, 0), (2, 1)}, • S 19 = S 12 ∪ {(0, 1)} \ {(3, 0)} = N 2 \ {(1, 0), (2, 0), (3, 0)}, • S 20 = S 12 ∪ {(0, 1)} \ {(4, 0)} = N 2 \ {(1,0), (2, 0), (4, 0)}, • S 21 = S 12 ∪ {(0, 1)} \ {(5, 0)} = N 2 \ {(1, 0), (2, 0), (5, 0)}.…”