Let's see some PPMI calculations. We'll use Fig. 6 .10, which repeats Fig. 6 .6 plus all the count marginals, and let's pretend for ease of calculation that these are the only words/contexts that matter. Figure 6 .10 Co-occurrence counts for four words in 5 contexts in the Wikipedia corpus, together with the marginals, pretending for the purpose of this calculation that no other words/contexts matter.