-- find the full list of usernames in our data set:
the-list-of |usernames> => ket-sort clean author rel-kets[author] |>

-- find the inverse-authors:
|null> => find-inverse[author] |>

-- find the word frequency lists for all our users:
freq-list-op |*> #=> coeff-sort word-ngrams[1] remove-prefix["text: "] body inverse-author |_self>
|null> => map[freq-list-op, freq-list] the-list-of |usernames>

-- find words unique to users:
|null> => find-unique[freq-list] |>