Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Look precise, but not !

The author has a good and precise approach. However, it seems to me that, as an active member of some organizations relating to the field, the author had opportunities to look at some paper works, he "cut and paste" without verifications ?!? I read up to Chapter 4 and found too many errors. I found the matrix in Ed 2.28 was wrong, Eq 2.60 mus have derivative operator in LHS, ..., but the result in Eq 2.41 ~ 2.50 were correct ! Eq.3.16 is correct, but its development is not precise (messy). I failed to prove Eq 4.23 and its consequences are correct !