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wbhart

2,458 karma · joined December 22, 2010

I am a computer algebra/computational number theory researcher. I spend most of my time maintaining the Flint C library, and the Nemo.jl and Singular.jl libraries. I also work on algorithms for fast arithmetic.

My favourite languages are C and Julia.

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wbhart··on Gemini with Deep Think achieves gold-medal standard at the IMO
I have not been working on formalization but theorem proving, so I can't confidently answer some of those questions.

However, I recognise that there is not so much training data for LLMs wanting to use the Lean language. Moreover, you are really teaching it how to apply "Lean tactics", which may or may not be related to what mathematicians do in standard texts on which LLMs have trained. Finally, the foundations are different: dependent type theory, instead of the set theory that mathematicians use.

My own personal perspective is that esoteric formal languages serve a purpose, but not this one. Most mathematicians have not been hot on the idea (with a handful of famous exceptions). But the idea seems to have gained a lot of traction anyway.

I'd personally like to see more money put into informal symbolic theorem proving tools which can very rapidly find a solution as close to natural language and the usual foundations as possible. But funding seems to be a huge issue. Academia has been bled dry, and no one has an appetite for huge multi-year projects of that kind.

wbhart··on Gemini with Deep Think achieves gold-medal standard at the IMO
Lean is an interactive prover, not an automated prover. Last year a lot of human effort was required to formalise the problems in Lean before the machines could get to work. This year you get natural language input and output, and much faster.

The advantage of Lean is that the system checks the solutions, so hallucination is impossible. Of course, one still relies on the problems and solutions being translated to natural language correctly.

Some people prefer difficult to read formally checked solutions over informal but readable solutions. The two approaches are just solving different problems.

But there is another important reason to want to do this reliably in natural language: you can't use Lean for other domains (with a few limited exceptions). They want to train their RL pipelines for general intelligence and make them reliable for long horizon problems. If a tool is needed as a crutch, then it more or less demonstrates that LLMs will not be enough in any domain, and we'll have to wait for traditional AI to catch up for every domain.

wbhart··on AlphaEvolve: A Gemini-powered coding agent for designing advanced algorithms
1. Correct

2. Correct, however you can use Waksman as a basecase and always beat Strassen (though it is not asymptotically better of course).

5. Possible, but even so, there is already an algorithm that will work with 46 real multiplications (and some divisions by 2). The real numbers are commutative and admit division by 2.

wbhart··on AlphaEvolve: A Gemini-powered coding agent for designing advanced algorithms
Z_2 has characteristic 2, not 0.
wbhart··on AlphaEvolve: A Gemini-powered coding agent for designing advanced algorithms
As already noted in a post by fdej further down, Waksman's algorithm from 1970, which works over the complex numbers, requires only 46 multiplications (and I guess, divisions by 2, which may or may not be relevant depending on your actual ring).
wbhart··on AlphaEvolve: A Gemini-powered coding agent for designing advanced algorithms
There's even an Open Source implementation of Waksman's in Flint, the package fdej maintains.
wbhart··on A cycle-accurate IBM PC emulator in your web browser
I've been using MartyPC for a few years and except for emulating glitches in hardware which depend on the manufacturer, date of manufacture or even temperature, it is getting harder to find cycle accurate tricks that MartyPC can't emulate perfectly (believe me, we've been trying).

The whole thing is a marvel of software engineering!

What is remarkable is that the author (GloriousCow) doesn't complain that people are ripping off his code and ideas, but that more people haven't used his learnings to create other cycle accurate emulators for the PC.

wbhart··on What we learned copying all the best code assistants
This blog article is written in a very engaging way. It seems to be more or less a masterclass on how to keep someone's attention, although there is no meta-story making you wait for the big fulfillment at the end.

I think it is the short, punchy sections with plenty of visuals and the fact that you are telling a story the whole way through, which has a natural flow, each experiment you describe, leading to the next.

wbhart··on The Theory of Topos-Theoretic 'Bridges' – A Conceptual Introduction (2016)
This is an interesting article, but the absence of simple examples of theories and their toposes and invariants made it seem a little abstract. Surely if the technique is so powerful, there ought to be easy examples of it aplenty.
wbhart··on 'A-team' of math proves a critical link between addition and sets
I doubt that he was intending a burn here. He's not talking about user interface issues or the like.

He's most probably, I would assume, talking about the well-known issue that formalisation tools require knowledge that a standard mathematician doesn't possess, such as the names of all the Lean tactics, how to locate the right theorem to use in mathlib (the Lean library), the necessity to write mathematics in a very formal language which is based on dependent type theory rather than based on sets (which is what most mathematicians are used to), etc.

Moreover, formalised mathematics does not work with natural language (and perhaps can't), and it will not accept informal or intuitive arguments. There are a lot of very fiddly things that have to be attended to. One can't assume that the reader is a skilled mathematicians who can easily fill in trivial details, as when writing a maths paper for expert readers.

But the Lean people are acutely aware of all of this. In my opinion he's not so much offering them much needed criticism so much as acknowledging one of the known barriers to mathematicians from outside the formalisation community getting into formalisation.

This is a major point of the article, that real, serious mathematicians have broken through that barrier recently, and it's not the first time. So things have improved enough to show that it is possible for seriously committed mathematicians to do this, even famous ones!

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
The field is fairly new to me. I'm originally from computer algebra, and somehow struggling into the field of ATP.

The most interesting papers to me personally are the following three:

* Making higher order superposition work. https://doi.org/10.1007/978-3-030-79876-5_24

* MizAR 60 for Mizar 50. https://doi.org/10.48550/arXiv.2303.06686

* Magnus Hammer, a Transformer Based Approach to Premise Selection. https://doi.org/10.48550/arXiv.2303.04488

Your mileage may vary.

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
Yes, there are various approaches like tree-of-thought. They don't fundamentally solve the problem because there are just too many paths to explore and inference is just too slow and too expensive to explore 10,000 or 100,000 paths just for basic problems that no one wanted to solve anyway.

The problem with solving such problems with LLMs is that if the solution to the problem is unlike problems seen in training, the LLM will almost every time take the wrong path and very likely won't even think of the right path at all.

The AI really does need to understand why the paths it tried failed in order to get insight into what might work. That's how humans work (well, one of many techniques we use). And despite what people think, LLMs really don't understand what they are doing. That's relatively easy to demonstrate if you get an LLM off distribution. They will double down on obviously erroneous illogic, rather than learn from the entirely new situation.

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
Sure, but people have already applied deep learning techniques to theorem proving. There are some impressive results (which the press doesn't seem at all interested in because it doesn't have ChatGPT in the title).

It's really harder than one might imagine to develop a system which is good at higher order logic, premise selection, backtracking, algebraic manipulation, arithmetic, conjecturing, pattern recognition, visual modeling, has a good mathematical knowledge, is autonomous and fast enough to be useful.

For my money, it isn't just a matter of fitting a few existing jigsaw pieces together in some new combination. Some of the pieces don't exist yet.

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
People have done experiments trying to get GPT-4 to come up with viable conjectures. So far it does such a woefully bad job that it isn't worth even trying.

Unfortunately there are rather a lot of issues which are difficult to describe concisely, so here is probably not the best place.

Primary amongst them is the fact that an LLM would be a horribly inefficient way to do this. There are much, much better ways, which have been tried, with limited success.

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
How on earth could you evaluate the scaling path with too little information. That's my point. You can't possibly know that a technology can solve a given kind of problem if it can only so far solve a completely different kind of problem which is largely unrelated!

Saying that performance on grade-school problems is predictive of performance on complex reasoning tasks (including theorem proving) is like saying that a new kind of mechanical engine that has 90% efficiency can be scaled 10x.

These kind of scaling claims drive investment, I get it. But to someone who understands (and is actually working on) the actual problem that needs solving, this kind of claim is perfectly transparent!

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
I think maybe I didn't make myself quite clear here. There are already algorithms which can solve advanced mathematical problems 100% reliably (prove theorems). There are even algorithms which can prove any correct theorem that can be stated in a certain logical language, given enough time. There are even systems in which these algorithms have actually been implemented.

My point is that no technology which can solve grade school maths problems would be viewed as a breakthrough by anyone who understood the problem. The fundamental problems which need to be solved are not problems you encounter in grade school mathematics. The article is just ill-informed.

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
There are certainly efforts along the lines of what you suggest. There are problems though. The number of backtracks is 10^k where k is not 2, or 3, or 4.....

Another issue is that of autoformalisation. This is the one part of the problem where an LLM might be able to help, if it were reliable enough (it isn't currently) or if it could truly understand the logical structure of mathematical problems correctly (currently they can't).

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
I've tested GPT-4 on this and it can be induced to give up on certain lines of argument after recognising they aren't leading anywhere and to try something else. But it would require thousands (I'm really under exaggerating here) of restarts to get through even fairly simple problems that professional mathematicians solve routinely.

Currently the context length isn't even long enough for it to remember what problem it was solving. And I've tried to come up with a bunch of ways around this. They all fail for one reason or another. LLMs are really a long, long way off managing this efficiently in my opinion.

wbhart··on OpenAI researchers warned board of AI breakthrough ahead of CEO ouster
I feel very comfortable saying, as a mathematician, that the ability to solve grade school maths problems would not be at all a predictor of ability to solve real mathematical problems at a research level.

The reason LLMs fail at solving mathematical problems is because: 1) they are terrible at arithmetic, 2) they are terrible at algebra, but most importantly, 3) they are terrible at complex reasoning (more specifically they mix up quantifiers and don't really understand the complex logical structure of many arguments) 4) they (current LLMs) cannot backtrack when they find that what they already wrote turned out not to lead to a solution, and it is too expensive to give them the thousands of restarts they'd require to randomly guess their way through the problem if you did give them that facility

Solving grade-school problems might mean progress in 1 and 2, but that is not at all impressive, as there are perfectly good tools out there that solve those problems just fine, and old-style AI researchers have built perfectly good tools for 3. The hard problem to solve is problem 4, and this is something you teach people how to do at a university level.

(I should add that another important problem is what is known as premise selection. I didn't list that because LLMs have actually been shown to manage this ok in about 70% of theorems, which basically matches records set by other machine learning techniques.)

(Real mathematical research also involves what is known as lemma conjecturing. I have never once observed an LLM do it, and I suspect they cannot do so. Basically the parameter set of the LLM dedicated to mathematical reasoning is either large enough to model the entire solution from end to end, or the LLM is likely to completely fail to solve the problem.)

I personally think this entire article is likely complete bunk.

Edit: after reading replies I realise I should have pointed out that humans do not simply backtrack. They learn from failed attempts in ways that LLMs do not seem to. The material they are trained on surely contributes to this problem.

wbhart··on GPT-4 is not getting worse
The tendency to begin summarising is very annoying. I'd assumed it was because of limited attention span of human raters who rated summarised or shorter outputs more highly. And I'd assumed this had been there from the beginning.

I encountered it when doing some research into getting GPT-4 to reliably multiply n-digit numbers. Up to 8x8 multiplications it doesn't do this very much, but by 10x10 it is almost impossible to get it to stop doing it.

When the multiplications become even larger, it seems to be literally impossible to prevent.

wbhart··on A Harvard professor became the world’s leading alien hunter
One mildly good thing to say about Loeb is that he spoke out very harshly about the quantum woo that the UAP "whistleblower" David Grusch invoked to potentially explain how aliens got here without travelling great distances (something about the "holographic principle", which really hasn't got anything to do with aliens appearing "in our dimension").

If you go back through news articles from 2017, 2019 and 2021 you will find that some "academy to the stars" claimed to have retrieved parts of crashed UAPs. There's some woo about how holding it near people had strange effects on them. They put it under a microscope and found some layered lead-bismuth alloy that had no known use on earth. And they found something that resembled frog skin.

So you have crashed UAPs, reverse engineering and non-human biologics. They even tried selling the reverse engineered tech back the Government through I think Bigelow aerospace. So that's who is behind the current UAP push.

There's also some folklore circulating about pilots having their brains literally scrambled by these UAPs.

Loeb at least sees through all this and speaks out against it. But all he seems to have is some spherules of metal from the bottom of the ocean which I'd say he has little to no evidence even came from space, let alone from a crashed UAP.

Unfortunately, if you look far enough into these things, you just find a trail of cash, extracted one way or another from a scientifically illiterate general public.

I'm not sure what the answer is. Yes, we need to look, which means spending money. But we need to make sure it isn't going into the pockets of pseudoscientists and people who use "classification" to cover up their (non-reputable) sources.

wbhart··on Discovering faster matrix multiplication algorithms with reinforcement learning
The new 4x4 matrix multiplication over F_2 has practical applications as many matrix operations over F_2 can be reduced to matrix multiplication.

For anyone looking for the algorithm itself, it is actually given in in one of the extended data sections at the very end of the paper.

wbhart··on Area 5150: 8088 MPH gets a successor
Technically it all runs in 500kb I think (not sure if this includes DOS). And this was intentional because the guys had in mind what people would typically have available.

However I think everyone is going to have to temper expectations regarding what this will run on. Even my effects (the 3D Glenz objects) couldn’t be debugged on an emulator even though it’s a fairly simple tricked up video mode and a bunch of fairly ordinary assembly code doing VRAM writes that are not timing critical for the screaming fast 3D.

wbhart··on Area 5150: 8088 MPH gets a successor
Actually the RAM was expanded in this demo out to 640kb. This was necessary for some of the effects in combination with the loader. Such expansion boards were available back in the day.
wbhart··on Investigators say they've finally identified the Zodiac Killer
According to an article on PubMed, that's largely a myth, based on early, faulty studies [1].

[1] "Low incidence of cardiovascular disease among the Inuit--what is the evidence?"

wbhart··on Google outage – resolved
I'd expect within seconds that Google is alerted of a very large number of issues with their servers and that the status page would be updated (the green light going to red) within seconds. It's now quite some time after the start of the outage and everything is still green on that status page.
wbhart··on Ramstein air base in Germany experiences potential incoming missile scare
There's a lot of us here due to the University. I know some of them personally.
wbhart··on Ramstein air base in Germany experiences potential incoming missile scare
I'm on the west yes. But you don't hear planes? It's a constant conveyor belt, even across the city!
wbhart··on Ramstein air base in Germany experiences potential incoming missile scare
There actually was a very loud alarm. From memory it was about 9:30am this morning (technically yesterday). One can hear the alarms on the base from Kaiserslautern fairly easily, though normally they are just drills.
wbhart··on YouTube will now show ads on all videos even if creators don’t want them
If I were a business, the answer is no, the regulations are very strict.

But I am not a business, I'm a hobbyist. I derive no income from my channel.

By my estimation you would need at least five employees in Germany to run an online business properly, as the law that governs businesses is voluminous and bureaucratic. I could not afford to run a business.

For example, if I were a business in Germany, other YouTubers could sue me simply because I didn't follow packaging or E-waste laws in one of my videos. And that is to say nothing of surprise laws that you couldn't even predict would be laws.

Also, under German law I'd need permission from my existing employer to run a business, which they would not likely give.

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