Hence, the number of random subcorpora of size k to forge by sampling is defined by (1 − k/n) kx ≤ t, which yields: x ≥ log t k log (1 − k/n) Processing at least x random subcorpora of size k will thus ensure a proper coverage of the input corpus.
rather than setting in advance some particular degree of coverage (hence imposing a fixed number of subcorpora to process), we deduce from the above result a probability distribution to randomly draw the sizes of the subcorpora to process: The numerator (log t) was substituted for −1 because t is a constant: t ≤ 1 ⇒ log t ≤ 0.