Section 3.1.1

Difficult: I wasn't able to really follow the proof of Lemma 3.1.1. I don't see how we transfer from the set of F9k) for all k element of the Naturals, then limit it to a single f(k) and then re-apply it to all f(k).

Reflective. I think that it is interesting that there are so many proofs of the infinitude of primes, and that they all show us something a little different about the primes.