Richard Borcherds | Monstrous Moonshine: From Group Theory to String Theory | The Cartesian Cafe

[@MitchellPorter2025]

Certainly my favorite of your podcasts. Borcherds is very likable, he did this inspirational legendary thing, and I suspect that the *entirety* of his proof has a string-theoretic interpretation (revolving around the j-function being the 1-loop partition function of the bosonic string compactified on the Leech lattice), which is good for people who grok string theory, since it means e.g. that there must be a "physical" way to understand all that lore about exponential GKMAs and generalized Dynkin diagrams. So that's exciting. :-)

[@simonburton992]

good job asking questions & great to see how patient & generous Borcherds is. Thankyou.

[@gerardopc1]

Glad to see you're back, Tim. Greetings from Mexico 🇲🇽🙋🏽‍♂️

[@haroldhamburgler]

30:35 What Professor Borcherds said here is entirely correct and there was no need for a correction. He was just giving the simplest example on an involution, not specifically an involution of a simple group. (12) is indeed an involution of S5, but it is not even an element of A5. One involution for A5 would be (12)(34). In general, an involution is an element who's square is the identity.

[@TimothyNguyen]

The correction in the lower right note was to correct what Richard literally said: "S_n isn't quite a group". I think it's obvious that he forgot to say "simple" but I wanted to be sure there was no confusion.

[@haroldhamburgler]

I think he does say it “isn’t quite a simple group,” though I now notice that the audio is crappy while he is saying the word simple.

[@persistenthomology]

thank you for making this

[@tomholroyd7519]

Martin Gardener!! He enthused us all.

[@dnavas7719]

keep them coming!

[@JAYMOAP]

Very nice, Richard is great 👍👌

[@Raspberry_aim]

These are great. Thank you!

[@glyde570]

didnt expect to see you here :)

[@Raspberry_aim]

Unexpected indeed haha@@glyde570

[@JAYMOAP]

Timothy, I would like to use 2 min of this conversation in my video, I hope that is ok with you

[@TimothyNguyen]

Sure can you please attribute the clip to The Cartesian Cafe?

[@JAYMOAP]

@@TimothyNguyen of course, wouldn't even need to mention :) much appreciated Timothy

[@robmorgan1214]

Try and interview Wojciech Zurek on the topic of Born's rule, quantum darwinism, and the no cloning theorem. After that, if you don't understand quantum mechanics, you never will. Contrary to popular opinion, there's really not much to it... most people just can't cope when the behavior of the universe interferes with the projection operator of their ego onto the universe. They take the zero expectation value as an insult rather than a simple demonstration of orthogonality.

[@portport]

"No distractions like cryptocurrency that all the smart people are going into" 😂

[@ollienoble9683]

Hey Timothy! Chris lehto released a new unified firleld theory today, please take a look for us 🙏

[@kyaume21]

Omg, at points this seemed to have turned into a third degree interrogation. 😂 All for the good, but sometimes getting to the point like where Godel was interrogated by an immigration officer asking whether he had really destroyed German mathematics, and what he had in mind for American mathematics.😮 And poor Richard didn't even have an Einstein or a Morgenstern at his side.😢

[@tomholroyd7519]

Yo Michael Penn

[@vedantbhutra1118]

[Deleted]

[@TimothyNguyen]

The outline is already in the video description.

[@vedantbhutra1118]

Oh my apologies. I hadn’t seen it