But I think FLT is about as far as one can get from that situation! Wiles's work was the culmination of centuries of theory-building work, and the concepts that were developed over that time are far more important than FLT; the thing Wiles actually proved (a special case of something called the "Modularity Theorem", the full version of which was proved a bit later) is itself much more valuable to human understanding of mathematics than FLT. It's certainly very cool that it can be used to answer such a simple question that was open for so long, and it makes for a great headline, but I think if you asked number theorists working in the area they would almost all tell you that they're much more grateful for the theory that came out of this quest than for the mere fact that the quest was completed.

If a product like this worked well --- and I agree Andrew Ng's involvement seems like a positive sign --- then that would be great! Something I would wonder about from my past experience using LLM's for technical subjects is how to replicate a particular side of the student-teacher relationship. Sometimes a new student of mine will need to be told that they don't actually understand something as well as they think they do, and that they'd be better served by going more slowly than they might have wanted to. This "talking you down gently" conversation is one I'm happy to have (and sometimes it's actually me who's wrong!) but I'd be interested to see whether and how well an LLM run by a company that really wants to retain customers could pull this off.

It's hard to say without an actual product, of course. I'm looking forward to seeing what they come out with.

But this tweet paints a somewhat misleading picture of the role peer review plays in practice in modern math research. Reading this tweet could leave you with the impression that when someone proves a new result, no one pays any attention until it's gone through peer review and published in a journal. This just isn't true. ArXiv preprints are much more widely read than the journals' version of articles, and they go up essentially as soon as they're written. Certainly no one's waiting the year-plus it would take to get the article published in a journal! And even before that, mathematicians communicate their results to each other through slightly less formal channels, like blogs, conference talks, and regular human word of mouth.

In short, despite the sclerotic and parasitic nature of the journal system, the way ideas get disseminated in the field in practice is actually a lot closer to the ideal prewar picture he's describing in the tweet. I'm led to understand that this was less true before the Internet, but even by the time I started my PhD in 2009 things had been working the way I just described for quite a while.

But "what mathematicians care about" is much, much broader than what gets you published in a fancy journal. Mathematics as a human activity is millennia old, much older than the concept of journals or even universities, and that activity is, to me, very beautiful, worth preserving, and more of an art than a game. The incentive structure of academia for the past few decades has done a pretty bad job at preserving that art form, but that doesn't mean mathematicians as actual human beings don't care about it --- if they didn't, they probably would have chosen a different career.

Some math research does involve grabbing a single, fully specified conjecture off the shelf and hunting for a proof of it, and it's true that if you manage to solve a long-standing open problem, other mathematicians will be interested no matter how you did it.

But this isn't all of what they do, probably not even most of what they do. Like in software engineering, it's not always obvious which question would be the most useful one to ask. A lot of mathematical work also goes into what we call "theory-building", where you could say that primary work goes into coming up with definitions rather than theorems. Mathematicians also care a great deal about how something is proved; a lot of them are some of the most aesthetically picky people I've ever met. Words like "ugly", "beautiful", "creative", and "boring" are used to describe both definitions and proofs all the time.

From the outside, it can look like all they're doing is pumping out proofs at any cost. But I promise you that when I talk to mathematicians who don't have any experience building software, they have a similarly narrow view of that field as well! Both fields, from the inside, look a lot more human than you might expect.

In order to get a Ph.D., you have to do some sort of original research, so in that sense you're working on "previously unsolved stuff" basically right from the start. But that doesn't entail doing anything all that ground-breaking; most Ph.D. dissertations (very much including mine!) contain work that a more senior researcher in the same subfield could probably have produced without too much difficulty. The software development analogy is a pretty good one: a lot of the point of getting junior researchers to do research is to help train them to one day become senior researchers, and often the work itself is nothing all that special.

Given the trajectory of these LLM proofs, this seems like it's going to have to change pretty soon, and to be honest I'm pretty grateful that I'm not in charge of deciding what that's going to look like, because I don't have any good ideas! I'm actually pretty worried about the future of the field.

Anyway, yeah, if this scenario does come to pass it will be interesting to see just how impenetrable the resulting formal proofs end up looking and how hard it is to turn them into something that humans can fit in their heads. I can imagine a continuum of possibilities here, with thousands of pages of inscrutable symbol-pushing on one end to beautiful explanations on the other.

I meant to be responding specifically to the case where some future theorem-proving LLM spits out a thousand-page argument which is totally impenetrable but which the proof-checker still agrees is valid. I think it's sometimes surprising to people coming at this from the CS side to hear that most mathematicians wouldn't be too enthusiastic to receive such a proof, and I was just trying to put some color on that reaction.

In general, though, the answer to this question would depend on the specifics of the argument in question. Sometimes you might be able to salvage something; maybe there's some other setting where same methods work, or where some hypothesis analogous to the false one ends up holding, or something like that. But of course from a purely logical perspective, if I prove that P implies Q and P turns out to be false, I've learned nothing about Q.

I'm actually prepared to agree wholeheartedly with what you say here: I don't think there'd be any realistic way to produce thousand-page proofs without formalization, and certainly I wouldn't trust such a proof without some way to verify it formally. But I also don't think we really want them all that much!

The ultimate reason I think is that what really lights a fire under most mathematicians is the desire to know why a result is true; the explanation is really the product, much more so than just the yes-or-no answer. For example, I was never a number theorist, but I think most people who are informed enough to have an opinion think that the Riemann Hypothesis is probably true, and I know that they're not actually waiting around to find out. There are lots of papers that get published whose results take the form "If the Riemann Hypothesis is true then [my new theorem]."

The reason they'd still be excited by a proof is the hope, informed by experience with proofs of earlier long-standing open problems, that the proof would involve some exciting new method or perspective that would give us a deeper understanding of number theory. A proof in a formal language that Lean says is true but which no human being has any hope of getting anything from doesn't accomplish that.

First, right now presumably the reason a few people still become master woodworkers is that their work is actually better than the mass-produced furniture that you can get for much less money. Imagine a world where instead it was possible to cheaply and automatically produce furniture that is literally indistinguishable from, or maybe even noticeably superior to, anything a human woodworker could ever make. Do you really think the same number of people would still spend years and years developing those skills?

Second, you've talked about business logic and "math experts at the company" a few times now, which makes me wonder if we're just referring to different things with the word "mathematics". I'm talking about a specific subset, what's sometimes called "pure math," the kind of research that mostly only exists within academia and is focused on proving theorems with the goal of improving human understanding of mathematical patterns with no particular eye on solving any practical problems. It sounds like you're focused on the sort of mathematical work that gets done in industry, where you're using mathematical tools, but the goal is to solve a practical problem for a business.

These are actually quite different activities --- the same individuals who are good at one stand a decent chance of being good at the other, but that's most of what they have in common, and even there I know many people who are much more skilled at one than the other. I'm not really asking anyone who doesn't care about pure math to start caring about it, but when I'm talking about the effect of AI on the future of the field, I'm referring specifically to pure math research.

But when you talk about "getting a lot more done," I want to ask, get a lot more done to what end? Despite what mathematicians sometimes write in their grant applications, resolving most of the big open problems in the field probably won't lead to new technologies or anything. To use the Riemann Hypothesis example again, most number theorists already think it's probably true, and there are a lot of papers being published already which prove things like "if the Generalized Riemann Hypothesis is true, then [my new result]".

No one is really waiting around just for the literal, one-bit answer to the question of whether RH is true; if we got that information and nothing else, I'm sure number theorists would be happy to know, but not a whole lot about the work being done in the field would change. It's not just being "satisfying to the curious"; virtually the entire reason we want a proof is to use the new ideas it would presumably contain to do more mathematics. This is exactly what's happened with the proof of the Poincare Conjecture, the only one of the Millennium Problems that's been resolved so far.

This is what I was lamenting in my comment earlier: the thing you're describing, where we set proof-finding models to work and they spit out verifiable but totally opaque proofs of big open problems in math, very well might happen someday, but it wouldn't actually be all that useful for anything, and it would also mean the end of the only thing about the whole enterprise that the people working in it actually care about.