8 Hence, we start generating sentence combinations n r in lexicographic order, for r = 1...n, and for each combination E i k = S i 1 , S i 2 , ..., S i k where k > 1, we generate additional extracts E ′ i k by successfully swapping S i j with S i k for j = 1, ..., k − 1 and checking to see if the above constraints are still satisfied.
from a combination with k sentences that satisfies the constraints, we might generate up to k − 1 additional extracts.