B.2: Possible mistake in trivial analysis of number of maximal independent sets

[postmath]

Near the end of the first section of B.2, we find the following:

Thus, the
number of maximal independent sets satisfies the recurrence M(n) ≤ 2M(n − 1), with
base case M(1) = 1. We can easily guess and confirm the solution M(n) ≤ (2^n) − 1. The
only subset that we aren’t counting with this upper bound is the empty set!

I'm not 100% confident in my understanding here, but if I understand what you're trying to do with the "easily guess and confirm", then that should be parenthesized as 2^(n-1) instead.