We saw a lot of different statements about primes today, so much so that you might be feeling a bit overwhelmed. For reference, here is a list of the properties we actually proved: An integer $n>1$ is composite if and only if it has a prime divisor $p\leq \sqrt{n}$. There are infinitely many primes. If \$p_1,p_2,p_3,\ldots, [...]