Theory of numbers: Euclid's theorem
Channel: Richard E Borcherds
Date: 22/01/2021

This lecture is part of an online undergraduate course on the theory of numbers.

We discuss Euclid's proof that there are infinitely many primes, and give a few variations of it showing that there are infinitely many primes in certain arithmetic progressions. 

A couple of typos pointed out in the comments:
Sheet 1 at the bottom: 13x39 should be 13x139
Sheet 4 (14:00): 2^2^6+1 should be 2^2^5 +1  

For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj52Qf7lc3HHvHRdIysxEcj1H