Missing "Probability Mass Function" text when referring to "pmf"

[kyirong6]

Very small issue I just noticed while going through the book is that in 9.7.3 there is a reference to "pmf" and a reference to calling a Probability Mass Function a "pmf" without ever mentioning the term in entirety:

9.7.3:

For that interpretation to be valid, we require that represent a (pmf). A pmf, over K classes, is defined as a K-dimensional vector with elements in the range that sums to 1.

Thanks!