nit: in "5. Not Exploiting Structure in the Matrix", the author says circulant matrices can be solved in O(n log_2 n) operations, where log_2 means "base 2" log

nit: in "5. Not Exploiting Structure in the Matrix", the author says circulant matrices can be solved in O(n log_2 n) operations, where log_2 means "base 2" log. This notation is unnecessary since different bases of logs (as long as the bases are constant and independent of n) only differ in a constant factor, the _2 is insignificant in the big O notation, so it's just O(n log n)