FIX to Indexing Highly Repetitive String Collections, Part I: Repetitiveness
In Section 3.9, I say that it is enough to make an attractor with the explicit
positions of the macro scheme. This is an error, since this set is easily made
of the alphabet size. A substring could cross a phrase boundary without
contanining an explicit symbol position, and the argument would not work.
Instead, we can choose the first position of each block to form the attractor.
This is of size b and now the argument is correct.
Noted by Hideo Bannai.