As an aside, the professor in question is Richard Borcherds, fields medalist. He is probably most well known for proving the “Monstrous Moonshine” conjecture of Conway and Norton that there is some sort of correspondence between modular functions and representations of the Monster Group. When the conjecture was made in the 1970s, it was purely because someone noticed that a certain number was the same as the cardinality of the monster group. It seemed a crazy coincidence, so John H Conway said (playfully) that it was “Moonshine”. Hence the name “Monstrous Moonshine”.
https://en.wikipedia.org/wiki/Monstrous_moonshine
He has a youtube channel with lectures in number theory, category theory and other things.